33 Either make the tree good, and his fruit good; or else make the tree corrupt, and his fruit corrupt: for the tree is known by his fruit. 34 O generation of vipers, how can ye, being evil, speak good things? for out of the abundance of the heart the mouth speaketh. 35 A good man out of the good treasure of the heart bringeth forth good things: and an evil man out of the evil treasure bringeth forth evil things. 36 But I say unto you, That every idle word that men shall speak, they shall give account thereof in the day of judgment. 37 For by thy words thou shalt be justified, and by thy words thou shalt be condemned. (Matthew 12:33-37 KJV)
A Tree Is Known by Its Fruit
Jesus was still speaking in a reply to the Pharisees who had accused him of using Beelzebub’s power to work miracles. Using their own slanderous and evil speech, Jesus exposed the evil in their hearts. Though the Pharisees claimed to be righteous, their speech revealed the malice and the hypocrisy of their hearts. Jesus illustrated this truth using two key comparisons: the tree and its fruit and the heart as a storehouse.
First, a tree is known by its fruit (Matthew 12:33), just as a person is known by their words. If the heart is good, the words will be good; if the heart is corrupt, the words will reflect that corruption. The Pharisees, despite their outward religious appearance, bore fruit that revealed their spiritual decay. True transformation begins not with external behavior but with a renewed heart (Ezra 10:44). Jesus exposed their hypocrisy to show that their opposition to His works proved the evil within them.
Second, Jesus rebuked the Pharisees as a “brood of vipers” (Matthew 3:7), linking them to the deceitfulness of the serpent (Matthew 12:34-35). Jesus explained that the heart is a treasury, and whatever is stored inside will overflow through speech. A person with a heart full of grace, wisdom, and love for God will speak words that edify and glorify God. In contrast, an evil person’s heart harbors corruption, and their words naturally dishonor God and harm others (Jeremiah 6:7). No one can consistently speak good things unless God’s grace has transformed their heart.
Jesus warned that every idle or careless word will be accounted for on the Day of Judgment (Matthew 12:36-37). God hears everything including the words spoken thoughtlessly (Psalm 139:4). Idle talk, which serves no good purpose, is displeasing to God and is often a mark of folly (Ephesians 5:4, Job 15:3). Unrepentant hearts will be condemned by their own words, while those who speak words of truth and righteousness will be justified (James 1:26). As Proverbs 18:21 states, “Life and death are in the power of the tongue.”
The Pharisees, blinded by pride, failed to see that their speech condemned them. For attributing Jesus’s miracles to the devil, they had both slandered and blasphemed against the Holy Spirit. Moreover, their speech shows that they have hardened their hearts and are unwilling to accept the truth.
From Jesus’s reply to the Pharisees, we learn that our speech reflects our spiritual condition. Evil people speak mockery, slander, profanity, curses, deceit, and so on because their hearts are in a state of corruption. The only way to speak words that are pleasing to God is to have a heart transformed by His grace. A good tree bears good fruit; a heart filled with righteousness will overflow with words of life.