The Old Testament Law commanded the Israelites not to unite in interracial marriage (Deuteronomy 7:3-4).
Deuteronomy 7:3-4 (NKJV)
3 Nor shall you make marriages with them. You shall not give your daughter to their son, nor take their daughter for your son. 4 For they will turn your sons away from following Me, to serve other gods; so the anger of the LORD will be aroused against you and destroy you suddenly.
Though, the reason for this was not principally racial in nature. Rather, it was religious. The reason God commanded against interracial marriage existed because individuals of other races were idolaters and worshippers of false gods. The Israelites potentially would stray from God if they intermarried with idol worshippers, pagans, or heathens.
A similar principle is laid out in the New Testament, but at a much different level: “Do not be yoked together with unbelievers. For what do righteousness and wickedness have in common? Or what fellowship can light have with darkness?” (2 Corinthians 6:14).(NKJV)
14 Do not be unequally yoked together with unbelievers. For what fellowship has righteousness with lawlessness? And what communion has light with darkness?
Just as the Israelites (believers in the one true God) were commanded not to marry idolaters, so Christians (believers in the one true God) are commanded not to marry unbelievers.
A person should be judged by his or her character, not by skin color. All of us should be careful not to show favortism to some, nor be prejudiced or racial to others (James 2:1-10, see especially verses 1 and 9). A Christian man or woman’s standard for selecting a mate should always be to find out if the person they are interested in is a Christian (2 Corinthians 6:14), someone who is born again by faith in Jesus Christ (John 3:3-5). Faith in Christ, not skin color, is the Biblical standard for choosing a spouse. Interracial marriage is not a matter of right or wrong, but of wisdom, discernment, and prayer.
James 2:1-10 (NKJV)
Beware of Personal Favortism
1 My brethren, do not hold the faith of our Lord Jesus Christ, the Lord of glory, with partiality. 2 For if there should come into your assembly a man with gold rings, in fine apparel, and there should also come in a poor man in filthy clothes, 3 and you pay attention to the one wearing the fine clothes and say to him, “You sit here in a good place,” and say to the poor man, “You stand there,” or, “Sit here at my footstool,” 4 have you not shown partiality among yourselves, and become judges with evil thoughts?
5 Listen, my beloved brethren: Has God not chosen the poor of this world to be rich in faith and heirs of the kingdom which He promised to those who love Him? 6 But you have dishonored the poor man. Do not the rich oppress you and drag you into the courts? 7 Do they not blaspheme that noble name by which you are called?
8 If you really fulfil the royal law according to the Scripture, “You shall love your neighbor as yourself,”[a] you do well; 9 but if you show partiality, you commit sin, and are convicted by the law as transgressors. 10 For whoever shall keep the whole law, and yet stumble in one point, he is guilty of all.
The only reason interracial marriage should be well-thought-out is because of the difficulties a mixed-race couple may experience because others will have a hard time accepting them. Many interracial couples experience discrimination and ridicule, sometimes even from their own families. Some interracial couples experience difficulties when their children have skin tones of different shades from the parents and/or siblings. An interracial couple needs to take these things into consideration and be prepared for them, should they decide to marry. Again, though, the only Biblical restriction placed on whom a Christian can marry is whether the other person is a member of the Body of Christ.