What is adultery and why does God hate it? Adultery is the breaking of a covenant between a husband and wife. The Scriptures call believers to keep the marriage bed pure and when one member of the union leaves the home in search of sexual or emotional fulfillment outside of their covenant promise the relationship is broken. This is of great importance to God for he compares the relationship of Christ and the church to the relationship of a married couple.
In this same way, husbands ought to love their wives as their own bodies. He who loves his wife loves himself. After all, no one ever hated his own body, but he feeds and cares for it, just as Christ does the church — for we are members of his body. “For this reason a man will leave his father and mother and be united to his wife, and the two will become one flesh.” This is a profound mystery — but I am talking about Christ and the church. (Ephesians 5:28-32)
A husband and wife’s relationship was supposed to serve as an image of how Christ sacrifices himself and unites himself to the redeemed, no matter how much we deserve to be abandoned. Christ fulfills the command not to commit adultery precisely because he is the picture of faithfulness to God and humanity. He is the only one ever to give himself up.