Jamieson, Fausset and Brown on Ezra 9:4

4. Then were assembled unto me every one that trembled at the words of the God of Israel, &c.--All the pious people who reverenced God's word and dreaded its threatenings and judgments joined with Ezra in bewailing the public sin, and devising the means of redressing it.

I sat astonied until the evening sacrifice--The intelligence of so gross a violation of God's law by those who had been carried into captivity on account of their sins, and who, though restored, were yet unreformed, produced such a stunning effect on the mind of Ezra that he remained for a while incapable either of speech or of action. The hour of the evening sacrifice was the usual time of the people assembling; and at that season, having again rent his hair and garments, he made public prayer and confession of sin.