John 19:2 Commentary, Thorns, Purple and Scarlet

Commentary on John 19:2 

And the soldiers twisted (πλέξαντες) together a crown (στέφανον) of thorns (ἀκανθῶν) and put it on his head (κεφαλῇ) and arrayed (περιέβαλον) him in a purple (πορφυροῦν) robe (ἱμάτιον).--John 19:2

καὶ οἱ στρατιῶται πλέξαντες στέφανον ἐξ ἀκανθῶν ἐπέθηκαν αὐτοῦ τῇ κεφαλῇ, καὶ ἱμάτιον πορφυροῦν περιέβαλον αὐτόν--John 19:2

This corresponds in Matthew's gospel as:

And they stripped him and put a scarlet (κοκκίνην) robe (χλαμύδα) on him, And they twisted together a crown of thorns and set it on His head. They put a staff in His right hand and knelt down before Him to mock Him, saying, "Hail, King of the Jews!"--Matthew 27:28-29

καὶ ἐκδύσαντες αὐτόν, περιέθηκαν αὐτῷ χλαμύδα κοκκίνην. Καὶ πλέξαντες στέφανον ἐξ ἀκανθῶν, ἐπέθηκαν ἐπὶ τὴν κεφαλὴν αὐτοῦ, καὶ κάλαμον ἐπὶ τὴν δεξιὰν αὐτοῦ· καὶ γονυπετήσαντες ἔμπροσθεν αὐτοῦ ἐνέπαιζον αὐτῷ, λέγοντες, Χαῖρε, ὁ βασιλεὺς τῶν Ἰουδαίων·--Matthew 27:28-29 Byzantine majority (the Alexandrian has several small variants, v 28 has the same words but order changed)

Mark 15:17 largely is the same as Matthew 27:28 in this case but instead uses John's color of purple:

And they clothed him with purple (πορφύραν), and platted (πλέξαντες) a crown of thorns (ἀκάνθινον), and put it about his [head],--Mark 15:17

καὶ ἐνδιδύσκουσιν αὐτὸν πορφύραν καὶ περιτιθέασιν αὐτῶ πλέξαντες ἀκάνθινον στέφανον·--Mark 15:17

Reconciling the colors will be discussed at the end of this article.

For the matter of the robe see my article on John 19:23.

In John 18, Pilate mockingly called Christ the king of the Jews. Here his soldiers continue the mockery in physical ways.

Soldiers/Cherubim

The Roman soldiers carrying spears/swords might be an allusion to the cherubim with the flaming sword in Genesis to protect the Garden and the Tree of Life:

So He drove out the man; and He placed at the east of the garden of Eden the cherubim, and the flaming sword which turned every way, to keep the way to the tree of life.--Genesis 3:24

Twisted (πλέξαντες) 

The root word according to a concordance is found:

πλέκω Gr4120

To fold, plait, entwine. 

Ex 28:14, Is 28:5, Mt 27:29, Mk 15:17, Jn 19:2

Exodus 28:14 is one of the many times John 19 seems to allude to Exodus 28 which is about Priestly attire, fitting for Christ.  

And you shall make two tassels from pure gold, intermingled with flowers, a work of braiding, and you shall place the braided [πεπλεγμένα, peplegmena] tassels on the small shields on their shoulder-straps on the front sides.--Exodus 28:14 NETS of LXX

καὶ ποιήσεις δύο κροσσωτὰ ἐκ χρυσίου καθαροῦ καταμεμιγμένα ἐν ἄνθεσιν ἔργον πλοκῆς καὶ ἐπιθήσεις τὰ κροσσωτὰ τὰ πεπλεγμένα ἐπὶ τὰς ἀσπιδίσκας κατὰ τὰς παρωμίδας αὐτῶν ἐκ τῶν ἐμπροσθίων--Exodus 28:14 LXX

The MT reads:

 and two chains [שַׁרְשְׁרֹת shar'sherot] of pure gold, wreathed work thou dost make them, work of thick bands, and thou hast put the thick chains on the embroidered [שַׁרְשְׁרֹת shar'sherot]  things.--Exodus 28:14

וּשְׁתֵּי שַׁרְשְׁרֹת זָהָב טָהוֹר, מִגְבָּלֹת תַּעֲשֶׂה אֹתָם מַעֲשֵׂה עֲבֹת; וְנָתַתָּה אֶת-שַׁרְשְׁרֹת הָעֲבֹתֹת, עַל-הַמִּשְׁבְּצֹת. --Exodus 28:14

In the above the second שַׁרְשְׁרֹת corresponds to πεπλεγμένα, while the first one is translated as κροσσωτὰ. Here the braiding is part of the garment of the priest, not worn on the head, the high priest wore a turban.

Sharsherot שַׁרְשְׁרֹת appears only 7 times in the MT, x2 in Exodus 28:14, 1 in Exodus 39:15, 1 Kings 7:17, 1 Chronicles 3:5, x2 in 2 Chronicles 3:16.

Isaiah 28:5 reads:

In that day the Lord Sabaoth will be the garland of hope, which is woven [πλακεὶς plakeis] of glory, to what is left of my people.--Isaiah 28:5 NETS of LXX

τῇ ἡμέρᾳ ἐκείνῃ ἔσται κύριος σαβαωθ ὁ στέφανος τῆς ἐλπίδος ὁ πλακεὶς τῆς δόξης τῷ καταλειφθέντι μου λαῷ --Isaiah 28:5 LXX

In that day the LORD of hosts will be a crown of glory, and a diadem [וְלִצְפִירַת v'litz'firat] of beauty, to the remnant of his people--Isaiah 28:5 ESV of MT

בַּיּוֹם הַהוּא, יִהְיֶה יְהוָה צְבָאוֹת, לַעֲטֶרֶת צְבִי, וְלִצְפִירַת תִּפְאָרָה--לִשְׁאָר, עַמּוֹ.--Isaiah 28:5 MT

 The LXX say the crown is woven. Perhaps, this can suggest Christ represents the faithful remnant of God's people.

 Thorns ἀκανθῶν 

Adam was punished/cursed with thorns:

We see the mention of thorns first,

And unto Adam He said: 'Because thou hast hearkened unto the voice of thy wife, and hast eaten of the tree, of which I commanded thee, saying: Thou shalt not eat of it; cursed is the ground for thy sake; in toil shalt thou eat of it all the days of thy life. Thorns also and thistles shall it bring forth to thee; and thou shalt eat the herb of the field.  In the sweat of thy face shalt thou eat bread, till thou return unto the ground; for out of it wast thou taken; for dust thou art, and unto dust shalt thou return.'--Genesis 3:17-19

 The same Greek word is used in Genesis 3:18 LXX "ἀκανθῶν"--thorn bush.

The crown of thorns as an allusion to Adam when he was banished from the Garden, and Christ took away that curse:

"..Let us thank Him who took away the curse by His thorns"--St Ephrem the Syrian, Nativity Hymn 3:18

Through the crown of thorns, which they put on him, they showed  and witnessed that he took away the curse of Adam.23  Through all with which they wanted to falsify his words, his truth was crowned by the false ones.--St Ephraim the Syrian, Hymns on the Crucifixion 4:2

St Cyril of Jerusalem (not to be confused with the same of Alexandria), largely agreeing with St Ephrem on Christ undoing the curse of Adam, its represents the forgiveness of sins, also links it to Christ cursing the fig tree:

for what though it be of thorns? Every king is proclaimed by soldiers; and Jesus also must in a figure be crowned by soldiers; so that for this cause the Scripture says in the Canticles, Go forth, O you daughters of Jerusalem, and look upon King Solomon in the crown wherewith His mother crowned Him. (Song of Songs 3:11) And the crown itself was a mystery; for it was a remission of sins, a release from the curse.  

Adam received the sentence, Cursed is the ground in your labours; thorns and thistles shall it bring forth to you. (Genesis 3:17-18)  For this cause Jesus assumes the thorns, that He may cancel the sentence; for this cause also was He buried in the earth, that the earth which had been cursed might receive the blessing instead of a curse. At the time of the sin, they clothed themselves with fig-leaves; for this cause Jesus also made the fig-tree the last of His signs. For when about to go to His passion, He curses the fig-tree, not every fig-tree, but that one alone, for the sake of the figure; saying, No more let any man eat fruit of you (Mark 11:1); let the doom be cancelled. And because they aforetime clothed themselves with fig-leaves, He came at a season when food was not wont to be found on the fig-tree. Who knows not that in winter-time the fig-tree bears no fruit, but is clothed with leaves only? Was Jesus ignorant of this, which all knew? No, but though He knew, yet He came as if seeking; not ignorant that He should not find, but showing that the emblematical curse extended to the leaves only.--St Cyril of Jerusalem, Catechetical Lecture 13:17-18

Rufinus also notes the connection with Adam:

It is written that there was put on Him a crown of thorns. Of this hear in the Canticles the voice of God the Father marvelling at the iniquity of Jerusalem in the insult done to His Son: "Go forth and see, you daughters of Jerusalem, the crown wherewith His mother has crowned Him." Moreover, of the thorns another Prophet makes mention: "I looked that she should bring forth grapes, and she brought forth thorns, and instead of righteousness a cry." But that you may know the secrets of the mystery, it behooved Him, Who came to take away the sins of the world, to free the earth also from the curse, which it had received through the sin of the first man, when the Lord said "Cursed be the earth in your labours: thorns: and thistles shall it bring forth to you." For this cause, therefore, is Jesus crowned with thorns, that first sentence of condemnation might be remitted.--Rufinus, Commentary on the Apostles' Creed 

Thorns in Syrian Christian and Jewish tradition

It is noteworthy that Jewish tradition believes the fig tree to be the Tree of knowledge of good and evil, which those in the Syrian tradition generally held to such as the Nestorian bishop of Mosul--Solomon of Akhlat in his Book of the Bee (His hands were nailed upon the wood of the fig-tree of which Adam ate, and behold, we have mentioned its history with that of Moses' rod.--Solomon of Akhlat, Book of the Bee, Chapter 44). 

St Aphrahat the Persian sage states:

Because of her the earth was cursed, that it should bring forth thorns and tares. Accordingly, by the coming of the offspring of the Blessed Mary the thorns are uprooted, the sweat wiped away, the fig-tree cursed, (Matthew 21:19) the dust made salt, (Matthew 5:13) the curse nailed to the cross, (Colossians 2:14) the edge of the sword removed from before the tree of life and it given as food to the faithful, and Paradise promised to the blessed and to virgins and to the saints.--St Aphrahat, Demonstrations VI

St Ephraim notes that bread mentioned following the toiling, sweating among thorns for food, and contrasts it with Christ and the Eucharist:

The beautiful staff that grew among the ugly tares gave the bread of life without toil to the hungry. He released the curse that held Him captive in Adam to eat by the sweat the bread of pains and thorns Blessed is he who eats from His blessed bread and makes pass away from him the curse--St Ephraim the Syrian, Hymn on Virginity 31:14 

The burning bush Moses encountered God in Exodus 3 is called סנה sneh, which specifically refers to a thorn bush (contrary to most English translations), in fact  Jesus and Stephen in Mark 12:26, Luke 20:37, Acts 7:30 uses a Greek word for the bush "batou" that refers to a thorn bush. 

Commenting on the Burning Bush, St Ephraim the Syrian notes:

"The bush which was unsuitable even as an image of dead gods was able to depict within itself the mystery of the living God. Moses, this is a sign to you; as you saw God dwelling in the midst of the fire, by fire you must serve the God who dwells in the fire."--St Ephraim the Syrian, Commentary on Exodus, p 232

On this passage, the editor refers to Ginzberg's Legends of the Jews: 

There were good reasons for selecting the thorn-bush as the vessel for a Divine vision. It was "clean," for the heathen could not use it to make idols. God's choosing to dwell in the stunted thorn-bush conveyed the knowledge to Moses that He suffers along with Israel. Furthermore, Moses was taught that there is nothing in nature, not even the insignificant thorn-bush, that can exist without the presence of the Shekinah. Besides, the thorn-bush may be taken as the symbol for Israel in several respects. As the thorn-bush is the lowliest of all species of trees, so the condition of Israel in the exile is the lowliest as compared with that of all the other nations, but as the thorn-bush releases no bird that alights upon it without lacerating its wings, so the nations that subjugate Israel will be punished. Also, as a garden hedge is made of the thorn-bush, so Israel forms the hedge for the world, the garden of God, for without Israel the world could not endure. Furthermore, as the thorn-bush bears thorns and roses alike, so Israel has pious and impious members, and as the thorn-bush requires ample water for its growth, so Israel can prosper only through the Torah, the celestial water. And the thorn-bush, the leaf of which consists of five leaflets, was to indicate to Moses that God had resolved to redeem Israel only for the sake of the merits of five pious men, Abraham, Isaac, Jacob, Aaron, and Moses. The numbers represented by the letters composing the Hebrew word for thorn-bush, Seneh, add up to one hundred and twenty, to convey that Moses would reach the age of one hundred and twenty years, and that the Shekinah would rest on Mount Horeb for one hundred and twenty days. Finally, in order to give Moses an illustration of His modesty, God descended from the exalted heavens and spake to him from a lowly thorn-bush instead of the summit of a lofty mountain or the top of a stately cedar tree. --Legends of the Jews, Volume II, Chapter 4: 303 (Moses in Egypt) by Louis Ginzberg

We see much can be applied to Christ, some seemingly cannot eg the 5 leaves representing 5 people that merited Israel's redemption--Christ alone merited the Church's, and also the gematria. The thorns can represent true worship and symbolizes God suffering with His people, just as Christ being God in Flesh suffered for His people. The thorns allude to a protective hedge--the Garden of God, something alluded to by John 19. The hedge protects the world--Christ's death appeased God's wrath, and by the prayers of the Church in the Mass the death of Christ is presented again. 

Lastly, as mentioned, the thorns represent God's modesty, a condescension, the kenosis mentioned in Philippians 2, where God leaves an exalted place and comes in a lowly form.

The Ram caught in the Thicket

When God called off the sacrifice of Isaac, a ram caught in a thicket was found by Abraham and sacrifice in place of Isaac. St Augustine, and others note this:

For when Abraham saw him, he was caught by the horns in a thicket. What, then, did he represent but Jesus, who, before He was offered up, was crowned with thorns by the Jews?--St Augustine, The City of God (Book XVI)

This ties in with my short article where I show a Jewish commentary that noted the sacrificing of Isaac was like a crucifixion. 

The Nestorian Solomon of Akhlat (absurdly) claims the cross was made of the wood of the tree used to offer the ram caught in the thicket. 

Thorns symbolizing idol worshippers becoming Christians

St Cyril of Alexandria commenting on the meaning of the thorns states:

And I have heard some say, and to some the conceit is well-pleasing, that the crown of thorns further signifies the multitude of idol-worshippers who will be taken up by Christ, as it were, into a diadem, through faith in Him; and they liken the Gentiles to barren and useless thorns, through their bearing no fruit of piety, and being rather fit to feed consuming fire----just like rubbish in the fields, just as wild thicket, which grows up without any culture--St Cyril of Alexandria, Commentary on the Gospel According to John, Book XII, on John 19:2

Lactantius states more eloquently:

For the placing of a crown of thorns upon His head, declared that it would come to pass that He would gather to Himself a holy people from those who were guilty. For people standing around in a circle are called a corona . But we, who before that we knew God were unjust, were thorns — that is, evil and guilty, not knowing what was good; and estranged from the conception and the works of righteousness, polluted all things with wickedness and lust. Being taken, therefore, from briars and thorns, we surround the sacred head of God; for, being called by Himself, and spread around Him, we stand beside God, who is our Master and Teacher, and crown Him King of the world, and Lord of all the living --Lactantius, Divine Institutes, Book IV (Of True Wisdom and Religion), Chapter 26

Thorns symbolize the Cares of the World that push aside Christ's gospel

St Augustine interprets the thorns in light of Jesus's parable:

“A sower went out to sow his seed. And as he sowed, some fell along the path and was trampled underfoot, and the birds of the air devoured it. And some fell on the rock, and as it grew up, it withered away, because it had no moisture. And some fell among thorns, and the thorns grew up with it and choked it. And some fell into good soil and grew and yielded a hundredfold.” As he said these things, he called out, “He who has ears to hear, let him hear.” And when his disciples asked him what this parable meant, he said....Now the parable is this: The seed is the word of God....And as for what fell among the thorns, they are those who hear, but as they go on their way they are choked by the cares and riches and pleasures of life, and their fruit does not mature. --Luke 8:4-15

 Origen states not to crown Christ with our thorns:

There are those who still have thorns with which they crown and dishonour Jesus, those, namely, who are choked by the cares, and riches, and pleasures of life, and though they have received the word of God, do not bring it to perfection. (Luke 8:14) We must beware, therefore, lest we also, as crowning Jesus with thorns of our own, should be entered in the Gospel and read of in this character by those who learn the Jesus, who is in all and is present in all rational and holy lives, learn how He is anointed with ointment, is entertained, is glorified, or how, on the other side, He is dishonoured, and mocked, and beaten. All this had to be said; it is part of our demonstration that our good actions, and also the sins of those who stumble, are embodied in the Gospel, either to everlasting life or to reproach and everlasting shame.--Origen, Commentary on the Gospel of John (Book I), Chapter 12

Thorns are sins

while saving us from the prickings of our sins, He refused not to submit His head to thorns--Pope Gregory the Great, Pastoral Rule (Book III), Chapter 12 

 St Thomas Aquinas quoting Bede the Venerable's commentary (which I cannot locate) states:

For instead of a diadem, they put upon Him a crown of thorns, and a purple robe to represent the purple robe which kings wear. Matthew says, a scarlet robe, but scarlet and purple are different names for the same color. And though the soldiers did this in mockery, yet to us their acts have a meaning. For by the crown of thorns is signified the taking of our sins upon Him, the thorns which the earth of our body brings forth. And the purple robe signifies the flesh crucified. For our Lord is robed in purple, wherever He is glorified by the triumphs of holy martyrs.--Catena Aurea on John 19:1-5

St Bede seems to tie it also with Genesis 3 curse allegorically. 

St Thomas Aquinas expanding on St Bede's comments states:

They mock him with a crown, because it is customary for kings to wear a crown, a crown of gold: "A crown of gold upon his head" (Sir 45:12). The Psalm (20:4) mentions this: "You set a crown of fine gold upon his head." And the soldiers plaited a crown of thorns, and put it on his head, the head of him who is a crown of glory to those who belong to him: "In that day the Lord of hosts will be a crown of glory, and a diadem of beauty, to the remnants of his people" (Isaiah 28:5). It was appropriately made of thorns, because by them he removes the thorns of sin, which pain us through remorse of conscience: "Break up your fallow ground, and sow not among thorns" (Jer 4:3). These thorns also take away the thorns of punishment which burdens us: "Thorns and thistles it shall bring forth to you" (Gen 3:18) --St Thomas Aquinas, Commentary on the Gospel of John, Chapter 19, Lecture 1

Head

The head suffers with the rest of the body, Christ the head

Robe

And the purple robe signifies the flesh crucified. For our Lord is robed in purple, wherever He is glorified by the triumphs of holy martyrs.--Bede the Venerable quoted in Catena Aurea on John 19:1-5

The Purple Robe symbolizes the Kingdom of God on Earth

the royal apparel, I mean the purple robe, they say, means Christ's Kingdom, which will be extended over all the world. --St Cyril of Alexandria, Commentary on the Gospel According to John, Book XII, on John 19:2

Purple and Scarlett

John says the robe was "purple" πορφυροῦν while Matthew "scarlet" κοκκίνην.

Most say that think the same garment is being referred whether it is scarlet or purple, the Diatessaron (a harmonization of the 4 gospels written by Tatian who would apostacize) seems to speak of two garments, one scarlet and one purple.

And they stripped him, and put on him a scarlet cloak. [John 19:2] And they clothed him in garments of purple--Diatessaron, Section 50

There is a Jewish tradition relating to how the priestly garments symbolize righteous (citing Isaiah 59:17):

R. Joshua of Siknin said in the name of R. Levi: It can be compared to a prince whose tutor wanted to go in before the King to plead on behalf of his son, but was afraid of those who stood by lest one of them should attack him. What did the king do? He clothed him in his royal purple cloak, so that all who saw him might be afraid of him. Similarly, Aaron used to enter the Holy of Holies almost hourly [on that day], and had it not been for the many merits which entered with him and helped him [in his petitions], he would have been unable to go in, on account of the angels that were there. For this reason did God give unto him [garments] after the pattern of the holy garments, as it says. And for Aaron's sons thou shalt make tunic, etc. (Ex. XXVIII, 40); just as it is written, And He put on righteousness as a coat of mail, and a helmet of salvation upon His head, and put on garments of vengeance for clothing, and was clad with zeal as a cloak (Isa LIX, 17)--Midrash Rabbah, Exodus. Chapter XXXVIII, 8-9 p 457 

Jewish tradition speaks about a story of a king with a purple garment that changes to red: 

"It can be compared to a king whose palace-guard sneered at his purple cloak. The king retorted: 'So. you have nothing to do except look at my purple cloak? Well, as long as you live, I will change it and punish you.' Similarly. the wicked who attacked 'the ancient of days' did not do so because He was old, but because they [they Israelites] had wearied him with their actions, for it says, Ye have wearied the Lord with your words (Mal II, 17). God said to them, 'I will change [my cloak], as it says, Wherefore is Thine apparel red? (Isa LXIII, 2), 'and I will punish you,' as it says, The Lord will go forth as a mighty man, He will stir up jealousy like a man of war (ibid XLII, 13)--Midrash Rabbah, Exodus, p 368

Bede the Venerable claims scarlet and purple in the case of the cloak refer to the same color; 

a purple robe to represent the purple robe which kings wear. Matthew says, a scarlet robe, but scarlet and purple are different names for the same color.--Bede the Venerable quoted in Catena Aurea on John 19:1-5

The colors are not exactly the same as St Bede says, there is some overlap (as seen below), since other scripture seems to distinguish the two:

 “Alas, alas, for the great city that was clothed in fine linen, in purple (πορφυροῦν) and scarlet (κόκκινον), adorned with gold, with jewels, and with pearls!"--Revelation 18:16

καὶ λέγοντες, Οὐαί, οὐαί, ἡ πόλις ἡ μεγάλη, ἡ περιβεβλημένη βύσσινον καὶ πορφυροῦν καὶ κόκκινον, καὶ κεχρυσωμένη χρυσίῳ καὶ λίθῳ τιμίῳ καὶ μαργαρίταις· --Revelation 18:16

Also, interesting, scarlet and purple are also the priestly colors in Exodus 28 (a chapter that reoccurs in John 19's allusions), which may be the chapter Revelation 18:16 is alluding to:

And they shall take the gold and the blue and the purple (πορφύραν) and the scarlet (κόκκινον) and the linen.--Exodus 28:5 NETS translation of the LXX

καὶ αὐτοὶ λήμψονται τὸ χρυσίον καὶ τὴν ὑάκινθον καὶ τὴν πορφύραν καὶ τὸ κόκκινον καὶ τὴν βύσσον--Exodus 28:5 LXX

But it could be there is some overlap between these colors, just as the Hebrew word commonly translated as "red" אֲדֻמָּה but can refers to red and brown, or a reddish brown--the color of blood. 

The κόκκινον word according to Liddle Scott Jones' lexicon says:

κόκκ-ι^νος=, η, ον, 

A. [select] scarlet, Herod.6.19, Ep.Hebr.9.19, PHamb.10.24 (ii A.D.), Plu.Fab.15; “κ. γενόμενος” blushing, Com.Adesp.19.3 D. 

II. [select] Subst. κόκκινα, τά, scarlet clothes, ἐν κ. περιπατεῖν, κ. φορεῖν, Arr.Epict. 3.22.10, 4.11.34; -“ων βαφαί” PHolm.21.41: sg., LXX Ex.25.4.

This just mentions scarlet and notes it is used of blushing.

It is interesting that the lexicon entry for κόκκινον simply has scarlet but then for πορφυροῦν it reads:

πορφυροῦν

        [select] purple, of stuff, cloths, etc., “π. φᾶρος” Il.8.221; “χλαῖνα” Od.4.115; “πέπλοι” Il.24.796; “δίπλαξ” 3.126, Od.19.242; “ῥήγεα” Il.24.645; “τάπητες” 9.200, Od.20.151; “σφαῖρα” 8.373; “χλάμυς” Sapph.64; σπάργανα, πτερά, Pi.P.4.114, 183; χλανίς, χιτών, Simon.37.11, B.17.52, cf. A.Pers.317, Hdt.1.50, E.Or.1457 codd. (lyr.), etc.

2. [select] of human complexion, bright-red, rosy, flushing, “π. Ἀφροδίτη” Anacr.2.3; “στόμα” Simon.72; “παρῇδες” Phryn.Trag.13; χείλη IG3.1376.

3. [select] purple-clad, in purple, Luc. Tim.20. 

4. [select] neut. pl. πορφυρᾶ purple colour or purple spots, Ael.NA17.33. 

5. [select] πορφυροῦν (sc. ἄνθος), τό, Woodfordia floribunda (an Indian shrub), Ctes.Fr.57.21.

6. [select] Adv. -ῶς, στύφειν mordant for purple, PHolm.24.37.--Liddle Scott Jones 

and Middle Liddle states: 

after Hom. (from πορφύρα) dark red, purple or crimson, Pind., Hdt., Trag. 

2. [select] purple-clad, in purple, Luc.

As can be seen, πορφυροῦν has shades of red with in its semantic domain, not just purple. When looking at the overlap in meaning the color of the robe, if only one was used was more reddish/scarlet than violet in our modern English speech. This may be why there is not much said by the Greek fathers on the matter--the colors had overlap and was not perceived as being a contradiction. 

Colors are not thought of the same in every language. For instance, in English we think of baby blue, dark blue, navy blue as all types of the same color, however in Russia baby blue is called galu'boy голубо́й, while what we call a darker blue is see-nee си́ній. 

Perhaps, St John saw it more purplish, or perhaps he deliberately wanted to use a more ambiguous word to overlap with the color of royalty.