The Mosaic Law strictly forbade intermarriage with the native Canaanites (Exod. 34:11-16; Deut. 7:1-5). Furthermore intermarriage with other non-Israelites had resulted in tragic consequences in Israel's earlier history (cf. 1 Kings 11:1-8).
"Thus the action in Ezra 10 is not directed against inter-Israelite marriages between the returnees and the peoples of the land' but specifically against Israel's old wilderness and early conquest enemies, namely, the Canaanite, Hittites, Perizzites, Jebusites, Amorites, Egyptians and Moabites (Ezra 9:1). It is upon this note of the conquest re-established' that the Book of Ezra ends."127
"Under these circumstances the spirit of the law demanded an application broader than its original application. Hence Ezra was justified in applying a law limited to Canaanites to all pagan foreigners, even the Egyptians who were originally explicitly excluded."128
Pulling out one's hair (v. 3) was and is an expression of extreme grief, violent wrath, or intense moral indignation (cf. Isa. 50:6). Ezra was not alone in his distress (v. 4). Ezra pulled out his own hair, but Nehemiah later pulled out the hair of his enemies (Neh. 13:25).
"A man's attitude toward God's Word is one of the ultimate criteria of his spirituality."129
