Read Deuteronomy 5:18
18 “You must not commit adultery. (NLT)
For some people, the Bible is a tedious sequence of ‘thou shalt nots’. But for those who follow Jesus, those apparently negative commands are doorways to a more positive way of life. This particular commandment is one example.
The Bible seems to forbid sexual relationships with those outside the marriage relationship. Sex has its proper time and place. While we may enjoy friendship within boundaries outside marriage with those of the opposite sex, sexual union is a breach of the command.
This commandment is not so much ‘anti sex’ as ‘pro faithfulness’. The idea is that God is faithful to us and doesn’t go looking around for some better sorts of people with whom to have relationship. He is faithful even when it hurts; he is faithful even if we are faithless.
Then again, faithfulness in marriage is more than just refraining from external sexual relationships. It is a wholehearted keeping of the vows. For example, a man who boasts that he has never committed adultery may yet not be faithful because he has lacked kindness and sensitivity to his partner. Marital faithfulness is not just abstinence from another commitment; it is positive embrace of the present commitment.
Much adultery is based on the myth that the grass is greener somewhere else. This commandment tells us to stick to our commitments. That tempting greener grass may yet conceal a swamp of regret and deceit and pain.