Here are just a few of the bible verses used to justify segregation are:

Genesis 28:1: "And Isaac called Jacob, and blessed him, and charged him, and said unto him, Thou shalt not take a wife of the daughters of Canaan."
Leviticus 19:19: "Ye shall keep my statutes. Thou shalt not let thy cattle gender with a diverse kind ..."
Deuteronomy 7:2-3: "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.
Deuteronomy 22:9: "Thou shalt not sow thy vineyard with diverse seeds: lest the fruit of thy seed which thou hast sown, and the fruit of thy vineyard, be defiled."