In Matthew 15:11, Jesus says, “It is not what goes into the mouth that defiles a person, but what comes out of the mouth; this defiles a person.” This verse raises an important question – why is it that words and speech defile a person more than physical actions or consumption? Let’s explore a few key reasons:
1. Words reveal the heart
Jesus explained that our words reveal the condition of our heart: “For out of the abundance of the heart the mouth speaks” (Matthew 12:34). What we say externally exposes what is happening internally. Hateful, angry, lustful, deceitful speech shows the sinful desires and attitudes that are present in our hearts.
As Proverbs 4:23 states, “Keep your heart with all vigilance, for from it flow the springs of life.” Our words are one of the main “springs” flowing from the heart. That’s why Jesus said evil words defile us, because they expose the evil within us.
2. Words impact others
Our speech not only reflects our own hearts, but can deeply impact others. Words have tremendous power – power to build up or tear down, encourage or discourage, heal or wound (Proverbs 18:21). Angry, abusive, gossiping, lying, vulgar speech can inflict serious damage on those around us.
Unwholesome talk harms both the speaker and the hearer, spreading defilement. “Let no corrupting talk come out of your mouths, but only such as is good for building up, as fits the occasion, that it may give grace to those who hear” (Ephesians 4:29).
3. Words can lead to action
A third reason words are so defiling is their power to influence actions, for good or evil. Angry threats often lead to violence. Vulgar jokes normalize immorality. Deceptive speech manipulates behavior. Gossip fuels strife and division.
On the positive side, wise and truthful words spur others toward righteous living. Scripture says, “The tongue of the wise commends knowledge” (Proverbs 15:2) and “a soft answer turns away wrath” (Proverbs 15:1). The right words at the right time can move people toward God.
4. Words have consequences
Words are not empty. They have real consequences in the spiritual realm and beyond. Jesus warned that “on the day of judgment people will give account for every careless word they speak” (Matthew 12:36). Meaningless chatter and crude jokes will be judged.
Proverbs 18:7 states that “a fool’s mouth is his ruin.” Reckless, foolish speech leads to destruction. Words of deception and hatred pave the way to hell, as Jesus said: “by your words you will be condemned” (Matthew 12:37).
In contrast, wise and edifying speech has enduring rewards: “Whoever keeps his mouth and his tongue keeps himself out of trouble” (Proverbs 21:23) and “the fruit of the mouth [brings] a harvest of righteousness” (Proverbs 18:20).
5. Words express devotion
What we say with our mouths demonstrates who or what we are devoted to. Vulgarity and blasphemy denote rebellion against God. Gossip signals allegiance to the divisive powers of darkness. Truth-telling exhibits faithfulness to Christ.
The mouth overflows from the heart’s allegiance: “For the mouth speaks what the heart is full of” (Matthew 12:34 NIV). So defiling speech proves a heart captive to sin, while righteous words display devotion to God.
6. Words access spiritual power
There is extraordinary spiritual power in our words, for good or evil. Scripture teaches that “life and death are in the power of the tongue” (Proverbs 18:21). For example, our praise invites God’s presence, while cursing and lies empower the demonic.
Paul writes that wholesome speech “is good for building up, as fits the occasion, that it may give grace to those who hear” (Ephesians 4:29). Through Spirit-led intercession and prophetic declaration, our words release God’s grace and power into people and situations.
7. Words shape reality
Related to the last point, our words shape reality on earth as it is in heaven. God spoke the world into existence: “And God said…” (Genesis 1). Jesus told us to speak to mountains and trees (Mark 11:23-24). Life-filled words create, while death-filled words destroy.
Proverbs 18:20 declares, “From the fruit of a man’s mouth his stomach is satisfied; he is satisfied by the yield of his lips.” There is creative power in our mouths to “eat” the fruit we desire through faith-filled declarations that release God’s Kingdom (Matthew 6:10).
8. Words access the non-physical
Words grant us access to invisible, spiritual realities, through prayer, praise, preaching, prophecy, and more. Our speech permits two-way communication between the natural and supernatural realms. Believers can release God’s spiritual power into earthly spheres through Spirit-led intercession, declarations, and more.
This is why the enemy tries so hard to control our mouths through deception, disobedience, fear, etc. – to restrict communication between realms. As Jesus said, “Things that proceed out of the mouth come from the heart” (Matthew 15:18), and the heart bridges natural and spiritual domains.
9. Words can sanctify or desecrate
The Lord told Moses that when the high priest entered God’s presence in the Holy of Holies, “He must not go outside the sanctuary and so desecrate the sanctuary of God” (Leviticus 21:12). In God’s presence, desecrating speech defiles the atmosphere.
In the New Covenant, believers are called God’s temple (1 Corinthians 3:16). The Holy Spirit abides in us. Therefore, what comes “out of our mouths” either sanctifies or desecrates the temple, just as the high priest’s words produced purity or defilement in the sanctuary.
10. Words hold sway in the unseen realm
Angels and demons respond to our words. God tells Moses that if he speaks God’s words to Pharaoh, “I will be with your mouth and teach you what to say” (Exodus 4:12). Jesus says angels “always behold the face of my Father in heaven” (Matthew 18:10), ready to heed His voice. Our speech moves angelic forces for good or evil.
Also consider the story of Peter’s denial of Jesus. The Lord told Peter, “before the rooster crows today, you will deny three times that you know me” (Luke 22:34). Jesus foresaw that Peter’s rash words would empower demonic activity intended to sift and destroy him (Luke 22:31). But Christ prayed that Peter’s “faith may not fail.”
In summary, our words carry weight in unseen realms, influencing angels/demons and accessing or restricting spiritual power and authority.
11. Words express worship
A key theme of Scripture is that our mouths were made to worship God. The psalmist says, “My mouth will speak the praise of the Lord” (Psalm 145:21). We were created to be “the people of his praise” (Isaiah 43:21). Jesus quotes the OT command, “You shall worship the Lord your God and him only shall you serve” (Luke 4:8).
When we use our mouths to praise, pray to, and proclaim truth about our Creator, this brings Him glory and express proper worship. But when we misuse our words, we are robbing God of the worship He deserves. That’s why idle, angry, fearful, vulgar, or false speech is so defiling – it cheapens God’s rightful worship.
12. Words manifest faith
Speech expresses genuine faith or unbelief. Jesus commends people for great faith when they say things like, “only speak the word, and my servant will be healed” (Matthew 8:8). The apostle Paul writes, “The word is near you, in your mouth and in your heart” (Romans 10:8). Our testimony births faith in others’ hearts: “I believed, and so I spoke” (2 Corinthians 4:13).
In contrast, Jesus rebukes the disciples for “little faith” when their lips speak doubt and fear (Matthew 8:26). Faith and fear both come “out of the abundance of the heart” through words. Put another way, the mouth testifies to the measure of one’s faith.
This explains why speech plays such an important role in spreading or restricting the Kingdom of God on earth. As ambassadors of Christ, believers are exhorted: “Let your speech always be gracious” (Colossians 4:6), so that our words will build others up in faith.
Conclusion
In summary, Jesus teaches that our words have immense spiritual power and consequences. Speech provides a window into our hearts, impacts others, leads to action, ushers in judgment or reward, access spiritual forces, shapes reality, expresses worship, and testifies to faith. When misused through deception, hatred, gossip, etc. words defile the speaker and hearer by spreading evil from the heart.
Therefore, as God’s temple indwelt by the Holy Spirit, we must guard our mouths diligently, speaking words that edify, encourage, bless, and praise. May our speech always be seasoned with grace and point others to Christ.