Both the Bible and science concur: there is no such thing as interracial marriage. The subdivisions of mankind that we refer to as "races" do not genetically exist. There is exactly one race of human beings. There are ethnic and cultural differences, but the biological differences are so slight that they cannot be said to represent a different life form.
Does the Bible say anything about interracial marriage?
In spiritual terms, there are two races of humans: Jesus-followers and everyone else; those with a heart of stone, and those with a heart of flesh (Ezekiel 11:19). Second Corinthians 6:14 prohibits Christians from marrying non-Christians. This law was paralleled in Israel in the Old Testament (Deuteronomy 7:3-4) which forbade the Israelites from marrying foreigners of a different religion. But there are many marriages and children of mixed ethnicity that are held up with honor. Caleb's father is called a Kenizzite (Numbers 32:12)—descended from one of the nations of Canaan. Rahab was from Jericho (Joshua 2). Moses' wife was a Cushite from Midian (Exodus 2:16-21)—as was her father who served as a counselor for Moses (Exodus 18:17-27). Ruth the Moabitess has an entire book dedicated to her and her faithfulness to her Jewish mother-in-law. In the New Testament, Timothy was the son of a Jewish mother and a Greek father, and a leader in the early church.
There seems to be a general pattern among interethnic marriages in societies. A group of men, whether explorers, traders, job-hunters, or refugees, will enter another country. They will intermarry with local women, to varying degrees. Such marriages will be socially acceptable until the arrival of one or more factors: fear that the local culture will become diluted, the introduction of slavery of others of the men's nationality, or possibly the introduction of women of the ethnic minority. Sex slavery of girls and women generally leads to a great amount of interethnic marriages, as does the combination of war with refugees. When native men are killed in war and refugees from that war immigrate in, interethnic marriages become common.
Barring the outside influence of foolish prejudice, native culture is a much bigger issue in relationships than skin color. A couple's ancestry does not matter as much as the individual's family upbringing. When things such as conflict resolution and expectations differ greatly, ethnicity takes a back seat—and such issues can certainly strain a marriage between two people of the same ethnic background.
There are both advantages and disadvantages to mixed-ethnic relationships. Family and culture may prove to be difficult. But the more interethnic marriages a society witnesses, the more normalized they become. And it has been hypothesized that children of mixed parentage may have genetic benefits as damaging recessive genes are minimized.
There is nothing unbiblical about interethnic relationships. In fact, when Miriam challenged her brother Moses' authority by criticizing his mixed-ethnic marriage, God not only backed Moses and Zipporah, He gave Miriam leprosy for her disloyalty (Numbers 12). As God told Samuel, "… the Lord sees not as man sees: man looks on the outward appearance, but the Lord looks on the heart" (1 Samuel 16:7).
What does the Bible teach about marriage?
In marriage how do the two become one flesh?
Should Christians date or marry non-Christians?
When is the right time for marriage?
Why did God allow polygamy in the Bible?
Truth about Marriage