The events that follow occurred about four months after Ezra arrived (compare Ezra 7:9; 10:9).
Intermarriage with non-Israelites was risky because Israelites might worship other gods and adopt harmful religious practices (compare Ezra 4:1–5; Deuteronomy 7:1–4).
the holy seed has been mixed: Literally the holy seed has intermingled itself. Israel was a holy covenant nation (Exodus 19:6) and was not supposed to engage in pagan practices (Leviticus 19:2–4; 20:6–8, 22–26). Therefore, the people were to avoid marrying those who might influence them to adopt such practices. When religious and political leaders married foreigners, they risked leading others astray and damaging Israel's unique identity as a holy people.