For they have taken of their daughters for themselves, and for their sons: so that the holy seed have mingled themselves with the people of those lands. 9:2
Trivia: Why did Ezra pull out the hairs on his head and beard?
The Israelites offend God by "taking" foreign wives and thereby corrupting "the holy seed." 9:2
Ezra tells the men that they must abandon their wives and children if they are to avoid God's wrath. 10:2-3, 10-12