What does the Bible say about what defiles a man?

In Matthew 15:10-11, Jesus emphasizes that it is not what enters a person's mouth that defiles them, but what comes out of it. This concept reflects a deeper spiritual reality that originates from the heart. Jesus clarifies further by stating in Matthew 15:18 that 'those things which proceed out of the mouth come forth from the heart, and they defile the man.' Therefore, it is the condition of one's heart that determines moral purity or defilement, illustrating the need for a transformed heart in order to produce good things.