What does Mark 7:21 mean?

In their zeal to keep the Mosaic Law, the scribes and Pharisees over-emphasize manmade traditions to the point that they nullify the law. They obsess over ceremonial uncleanness in fear that they may accidentally eat unclean food and, thereby, become unclean themselves. Jesus explains their foolishness; whether you are unclean as a person is dependent on your heart, not your diet.

"Heart" is from the Greek root word kardia. It is the core of our being from which our desires, thoughts, and judgments come. Our actions reveal the state of our hearts, they do not define our hearts. A hardened heart will cause a person to indulge in the evil deeds listed in this verse and the next.

"Evil" is from the Greek root word kakos and means inappropriate, harmful, or bad. "Thoughts," from the Greek dialogismos, doesn't mean flickering impulses but careful deliberations and machinations. When the scribes and Pharisees teach the people that it is more important to fulfill a rash oath than care for their parents, they do so after careful, but hard-headed, deliberation.

Most of the rest of the list is self-explanatory and several examples touch on the Ten Commandments. "Sexual immorality" means any improper sexual intercourse, whether it be adultery, fornication, homosexuality, incest, or bestiality.

This passage suggests a very important distinction between having an evil intent and being the victim of evil. A person is unclean if their heart pushes them into sexual sin. A person is not unclean if they are the victim of sexual assault. The shame of a victim of molestation, rape, or voyeurism is not from God. God does not see the person as damaged or sinful or unclean.