“wraps her waist.” The Hebrew is often translated, “girds her loins.” To “gird” is to wrap with a flexible band, like a belt or sash, and the loins are the hips and small of the back, the strong muscles that connect the upper and lower parts of the body. Effectively, to “gird the loins” is to wrap the waist. This is one of the verses in Proverbs 31 that is good evidence that the section is not just about women, but that the wife embodies Wisdom and the lessons apply to both men and women, because women did not tie up their clothing in the biblical culture.
“Girding up the loins” is an idiom, and it is difficult to translate. It comes from the biblical culture in which standard outer garb for men was a long, ankle-length robe (the woman’s outer robe was longer than the man’s, even sometimes touching the ground). The robe provided warmth and shelter from the elements, and it sometimes was used as a person’s blanket at night (cp. Exod. 22:27). Merchants would pull up the robe at the waist, tuck it in, and create a kind of pocket they could keep things in, and bribes were often hidden in the fold of the garment (see commentary on Prov. 21:4). But the long robe would get in the way when a man needed to fight, move fast or work hard, so he would gather it up and tie it at the waist so it would be short and out of the way. In contrast, a woman in the biblical culture would never “gird up her loins” by gathering up her garment so that her legs were exposed. However, if we understand the idiom was used to refer to people being prepared for action (see commentary on 1 Pet. 1:13), then we can see how an idiom that was used of male behavior could also apply to women.
[For more on Prov. 31:10-31 applying to both women and men, see commentary on Prov. 31:10.]