Adam Clarke on Ezra 9:3

I rent my garment and my mantle - The outer and inner garment, in sign of great grief. This significant act is frequently mentioned in the sacred writings, and was common among all ancient nations.

Plucked off the hair - Shaving the head and beard were signs of excessive grief; much more so the plucking off the hair, which must produce exquisite pain. All this testified his abhorrence, not merely of the act of having taken strange wives, but their having also joined them in their idolatrous abominations.