The reason for the law prohibiting plowing with an ox and an ass yoked together is not clear. The ox was considered to be a “clean” animal, the ass “unclean” (14.1-8). Another way to express this is “Do not hitch an ox and a donkey together when you plow the ground.”

Quoted with permission from Bratcher, Robert G. and Hatton, Howard A. A Handbook on Deuteronomy. (UBS Helps for Translators). New York: UBS, 2000. For this and other handbooks for translators see here .