Ye shall keep my statutes. Thou shalt not let thy cattle gender with a diverse kind: thou shalt not sow thy field with mingled seed: neither shall a garment mingled of linen and woollen come upon thee. Leviticus 19:19
(“Field” is a reference to descended offspring, and “garment mingled of linen of wollen” (other versions say “clothing mixed with two kinds of material”) refers to a person who is a hybrid of two different races.)
But I have said unto you, Ye shall inherit their land, and I will give it unto you to possess it, a land that floweth with milk and honey: I am the Lord your God, which have separated you from other people. Leviticus 20:24
And Israel abode in [bless and do not curse][bless and do not curse][bless and do not curse][bless and do not curse]tim, and the people began to commit whoredom with the daughters of Moab. And they called the people unto the sacrifices of their gods: and the people did eat, and bowed down to their gods. And Israel joined himself unto Baalpeor: and the anger of the Lord was kindled against Israel. Numbers 25:1-4
And when the Lord thy God shall deliver them before thee; thou shalt smite them, and utterly destroy them; thou shalt make no covenant with them, nor shew mercy unto them: Neither shalt thou make marriages with them; thy daughter thou shalt not give unto his son, nor his daughter shalt thou take unto thy son. For they will turn away thy son from following me, that they may serve other gods: so will the anger of the Lord be kindled against you, and destroy thee suddenly. Deuteronomy 7:2-4
Thou shalt not sow thy vineyard with divers seeds: lest the fruit of thy seed which thou hast sown, and the fruit of thy vineyard, be defiled. Deuteronomy 22:9
A bastard shall not enter into the congregation of the Lord; even to his tenth generation shall he not enter into the congregation of the Lord. Deuteronomy 23:2
(Where “bastard” in the KJV is used in this passage, the Hebrew is מַמְזֵר or “mamzer,” which means “mongrel race” in this context. The Greek Septuagint (LXX) uses “allogenes,” which is a combination of two Greek words, "allos" meaning other, and "genos" meaning race.)
And the children of Israel dwelt among the Canaanites, Hittites, and Amorites, and Perizzites, and Hivites, and Jebusites: And they took their daughters to be their wives, and gave their daughters to their sons, and served their gods. And the children of Israel did evil in the sight of the Lord, and forgat the Lord their God, and served Baalim and the groves. Judges 3:5-7
And the seed of Israel separated themselves from all strangers, and stood and confessed their sins, and the iniquities of their fathers. Nehemiah 9:2
And the rest of the people, the priests, the Levites, the porters, the singers, the Nethinims, and all they that had separated themselves from the people of the lands unto the law of God, their wives, their sons, and their daughters, every one having knowledge, and having understanding... Nehemiah 10:28
Now it came to pass, when they had heard the law, that they separated from Israel all the mixed multitude. Nehemiah 13:3