“Everyone who looks at a woman with lustful intent has already committed adultery with her in his heart” (Matthew 5:28)
According to the Bible, marriage is valuable and should be protected. A clear example is the commandment: “You shall not commit adultery” (Exodus 20:14). Adultery is considered a serious sin, not only because it hurts another person deeply, but because it damages the covenant of marriage, which is an image of the relationship between God and His people (see e.g. Hosea 2:19, Malachi 2:14). Faithfulness in marriage and a loving, respectful relationship with your spouse are of major importance.
Jesus picks up on this commandment, and explains that it goes far beyond physical purity. It includes the sin of looking at a woman (or a man) with lustful intent – that is a sin of the heart. God sees what is in our hearts, even if we manage to hide our sins from other people. This explanation of Jesus is actually nothing new. In the book of Exodus, we read: “You shall not covet your neighbor’s spouse” (Exodus 20:17). That is how far God’s commandments go. They are about the desires of our heart.
Is your heart pure? Is it washed clean by God’s grace?