Evil begins in the heart and eventually leads to action

¹⁴When He had called all the multitude to Himself, He said to them, “Hear Me, everyone, and understand: ¹⁵There is nothing that enters a man from outside which can defile him; but the things which come out of him, those are the things that defile a man. ¹⁶If anyone has ears to hear, let him hear!”

¹⁷When He had entered a house away from the crowd, His disciples asked Him concerning the parable. ¹⁸So He said to them, “Are you thus without understanding also? Do you not perceive that whatever enters a man from outside cannot defile him, ¹⁹because it does not enter his heart but his stomach, and is eliminated, thus purifying all foods?” ²⁰And He said, “What comes out of a man, that defiles a man. ²¹For from within, out of the heart of men, proceed evil thoughts, adulteries, fornications, murders, ²²thefts, covetousness, wickedness, deceit, lewdness, an evil eye, blasphemy, pride, foolishness. ²³All these evil things come from within and defile a man.”