RE: Ezra Chapter 9--- the purpose of his prayer was to ask God to forgive the "The people of Israel" (Hebrew race) from inter-marrying with the ungodly pagans of the Canaanites, Hittites, Perizzites, Jebusites, Ammonites, Moabites, Egyptians and Amorites. Their sin had nothing to do with "inter-racial" marriages. It was a matter of God's children yoking themselves with ungodly people. Regardless of one's faith and walk with the Lord, if our spouse is ungodly, they are more apt to wear us down to their level--- than we Believers are apt to win them to the Lord.
The old saying of "If you lay down with dogs, you can expect to catch their fleas" holds true to this lesson in Ezra Chapter 9.
"Do not be anxious for anything, but in everything, by prayer and petition, with thanksgiving [and with praise]--- present your requests to God, and the peace of God, which transcends [surpasses] all understanding, will guard your hearts and your minds in Christ Jesus."
Philippians 4:6-7 Holman Standard Bible