The image of Isaac's carrying wood on which he is to be burned adds enormous power to the story. A midrash relates this to a Roman (not Jewish) method of execution that was sometimes used on Jewish martyrs: "It is like a person who carries his cross on his own shoulder" (Gen Rab 56.3)--Genesis 22:6 footnote (pg 46) of "The Jewish Study Bible"
Here is what the document cited says according to the Socino Translation:
"AND ABRAHAM TOOK THE WOOD OF THE BURNT-OFFERING--like one who carries his stake on his shoulder. AND HE TOOK IN HIS HAND THE FIRE AND THE KNIFE..."--Genesis Rabbah 56:3 page 493 (also called Breshit Rabba)Of course, we can see why some want to use the word stake instead of cross, because that would be too Christian!