“grind flour.” This was ordinarily the work of women and slaves, but it is mentioned here in the context of the high-born women of Babylon because they would have had slaves to do that work.
“Thigh.” An idiom. The word “thigh” was often used euphemistically for the sexual organs because of their close proximity. Genesis 46:26 literally reads, “All the souls that came with Jacob into Egypt, which came out of his thigh” (cp. Exod. 1:5; Judg. 8:30). Numbers 5:21 contains a curse, the essence of which is that if a woman has committed adultery, then “her thigh will rot.” Also, it was a custom for a man to make a solemn oath while holding the penis and testicles of the one he was swearing to, just as Abraham said to his servant, “put your hand under my thigh” (Gen. 24:2, 9; 47:29).
Here in Isaiah 47:2, the highborn women of Babylon (“tender and delicate;” Isa. 47:1) will be forced to grind grain, a menial task. Their veils and their clothing will be stripped off and their genitals will be openly exposed, and they will be marched across the rivers into Persia. The ancient cultures had some very cruel practices, and publicly stripping people naked was one of them. This stripping naked in Isaiah 47 was done by the Persians. In Isaiah 7:20 it was done by the Assyrians, who had a reputation around the East for their cruelty.There were many sexual euphemisms in the biblical languages, just as there are in all languages. For the use of “feet” as a sexual idiom, see commentary on Isaiah 7:20.