Difficulties between Christians and non-Christians arise fundamentally over different value systems. In 2 Corinthians 6:14, the apostle Paul wrote, "Do not be unequally yoked together with unbelievers. For what fellowship has righteousness with lawlessness? And what communion has light with darkness?"
Here, the concept of being "unequally yoked" is a reference to the biblical prohibition against harnessing an ox and a donkey together because they would not make a good team (Deuteronomy 22:10). By citing this concept, Paul was teaching the Corinthians not to get involved with idolatry. Pagan worship and Christianity cannot be yoked together. As Paul asks, "What part has a believer with an unbeliever?" (verse 15).
When we consider marrying someone, we need to apply the same principle by asking, Will my future mate and I make a good team? Prior to marriage is the time to consider whether we are compatible with a potential mate. Compatible religious belief is one area that has the potential to provide great satisfaction or, if there is disagreement in the area of religion, great havoc.
Of course, we should understand that we are going to have much contact with nonbelievers as we live our lives and we are supposed to be lights to these people (Matthew 5:14). The principle of being properly teamed up with someone, however, is particularly relevant to close personal relationships, such as business deals and marriage.
When Christians enter into marriages with non-Christians, they can be tempted to give up their Christian values. Some proceed with marriages anyway, thinking they can work things out between themselves. In some cases, individuals with differing values do find ways to work together with their limitations. In other cases, they find that they are frustrated by their mate's different values. Children of such marriages can also be confused as they try to decide which parent to follow.
In evaluating a potential mate, it is also important to realize that not all professing Christians share the same beliefs or lifestyles. Today, "Christian" is a very general term. This is why it is important for potential mates to learn about each other's beliefs through communication and getting to know each other. Then wise, informed decisions can be made regarding a potential marriage.
God's way of life is a delight and pleasure. Not being able to fully share or appreciate this joy is a frustration for both the Christian and non-Christian. Because of this, the principle given by God through Paul is still valid today. Following it can help us have better relationships.