The teaching on what defiles a person is a significant theme in the New Testament, particularly in the teachings of Jesus Christ. This concept is primarily addressed in the Gospels, where Jesus challenges the prevailing Jewish understanding of purity and defilement, which was heavily focused on external rituals and dietary laws.

Biblical Context

The primary passage concerning this teaching is found in the Gospel of Matthew 15:10-20 and its parallel in Mark 7:14-23. In these passages, Jesus addresses the Pharisees and the crowd, emphasizing the distinction between external and internal sources of defilement.

Matthew 15:10-20 :

In Matthew 15:10-11, Jesus calls the crowd to Him and says, "Listen and understand. A man is not defiled by what enters his mouth, but by what comes out of it." This statement directly challenges the Jewish dietary laws that were central to the Pharisaic understanding of purity. The Pharisees and teachers of the law were concerned with ritual cleanliness, which included strict adherence to dietary restrictions and washing rituals.

Later, in Matthew 15:17-20, Jesus explains to His disciples, "Do you not yet realize that whatever enters the mouth goes into the stomach and then is eliminated? But the things that come out of the mouth come from the heart, and these defile a man. For out of the heart come evil thoughts, murder, adultery, sexual immorality, theft, false testimony, slander. These are what defile a man, but eating with unwashed hands does not defile him."

Mark 7:14-23 :

Similarly, in Mark 7:14-15, Jesus declares, "Listen to Me, all of you, and understand: Nothing that enters a man from the outside can defile him, but the things that come out of a man, these are what defile him." In Mark 7:18-23, He further elaborates, "Are you still so dull? Do you not understand? Nothing that enters a man from the outside can defile him, because it does not enter his heart, but it goes into the stomach and then is eliminated." He went on to say, "What comes out of a man, that is what defiles him. For from within the hearts of men come evil thoughts, sexual immorality, theft, murder, adultery, greed, wickedness, deceit, debauchery, envy, slander, arrogance, and foolishness. All these evils come from within, and these are what defile a man."

Theological Implications

Jesus' teaching on what defiles a person shifts the focus from external observance to the condition of the heart. This teaching underscores the importance of inner purity and moral integrity over ritualistic compliance. It highlights the idea that true defilement is a matter of the heart and is manifested through one's thoughts, words, and actions.

This teaching also foreshadows the New Covenant, where the emphasis is on internal transformation through the Holy Spirit rather than adherence to the ceremonial laws of the Old Covenant. It aligns with the broader biblical narrative that God desires mercy, justice, and a contrite heart over mere ritual sacrifice (cf. Hosea 6:6, Micah 6:6-8).

Practical Application

For believers, this teaching calls for introspection and a focus on cultivating a heart that aligns with God's will. It encourages Christians to prioritize spiritual and moral purity, recognizing that true holiness is reflected in one's character and conduct. This teaching also serves as a reminder of the transformative power of the Gospel, which purifies the heart and renews the mind, enabling believers to live in a manner that honors God.