King James Version

What Does Matthew 12:34 Mean?

Matthew 12:34 in the King James Version says “O generation of vipers, how can ye, being evil, speak good things? for out of the abundance of the heart the mouth speak... — study this verse from Matthew chapter 12 with commentary, cross-references, and original Greek word analysis.

O generation of vipers, how can ye, being evil, speak good things? for out of the abundance of the heart the mouth speaketh.

Matthew 12:34 · KJV


Context

32

And whosoever speaketh a word against the Son of man, it shall be forgiven him: but whosoever speaketh against the Holy Ghost, it shall not be forgiven him, neither in this world, neither in the world to come.

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.


Commentary

KJV Study Commentary
'O generation of vipers, how can ye, being evil, speak good things? for out of the abundance of the heart the mouth speaketh.' Jesus addresses Pharisees harshly: 'generation of vipers' (γεννήματα ἐχιδνῶν/gennēmata echidnōn, offspring of snakes)—John Baptist's same epithet (Matthew 3:7). The rhetorical question: 'how can ye, being evil, speak good things?' expects answer: you can't. Evil nature produces evil speech. The principle: 'out of the abundance of the heart the mouth speaketh' (ἐκ τοῦ περισσεύματος τῆς καρδίας τὸ στόμα λαλεῖ/ek tou perisseumatos tēs kardias to stoma lalei)—whatever fills the heart overflows through speech. Reformed theology sees this as demonstrating total depravity: evil heart inevitably produces evil expression. It also teaches that speech reveals character—what we say indicates what we are. The Pharisees' accusation (attributing Jesus's works to Satan) revealed their evil hearts. Modern application: our words—criticism, gossip, lies, blasphemy, or alternatively worship, encouragement, truth—reveal our hearts' condition.

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Historical & Cultural Context

Vipers were venomous snakes common in Palestine—deadly, deceptive (striking from concealment), and associated with evil. Calling Pharisees 'generation of vipers' was devastating insult questioning their spiritual legitimacy. They claimed Abraham as father; Jesus and John implied Satan was their true father (John 8:44). The heart/mouth connection was axiomatic in Jewish wisdom: Proverbs 4:23 ('Keep thy heart with all diligence; for out of it are the issues of life'), Proverbs 12:14 ('A man shall be satisfied with good by the fruit of his mouth'), Proverbs 18:21 ('Death and life are in the power of the tongue'). Jesus applied this: speech diagnostic of spiritual condition. Pharisees' evil words (attributing Spirit's work to Satan) proved evil hearts. Early church took this seriously: James 3:1-12 extensively discusses tongue's power and its revelation of heart. Throughout history, heresy trials often examined words carefully—what people say reveals what they believe. Modern psychology confirms: speech patterns reveal underlying attitudes, beliefs, values. Jesus's principle remains: listen to what people consistently say to understand their hearts.

Reflection Questions

  1. What does your habitual speech—words you use when unguarded—reveal about your heart's condition?
  2. How do you cultivate heart purity knowing that speech inevitably reveals inner reality?
  3. In what ways do Christians sometimes maintain external religious vocabulary while hearts remain far from God?

Original Language Analysis

Greek · 17 words
γεννήματα1 of 17

O generation

G1081

offspring; by analogy, produce (literally or figuratively)

ἐχιδνῶν2 of 17

of vipers

G2191

an adder or other poisonous snake (literally or figuratively)

πῶς3 of 17

how

G4459

an interrogative particle of manner; in what way? (sometimes the question is indirect, how?); also as exclamation, how much!

δύνασθε4 of 17

can ye

G1410

to be able or possible

ἀγαθὰ5 of 17

good things

G18

"good" (in any sense, often as noun)

λαλεῖ6 of 17

speak

G2980

to talk, i.e., utter words

πονηροὶ7 of 17

evil

G4190

hurtful, i.e., evil (properly, in effect or influence, and thus differing from g2556, which refers rather to essential character, as well as from g455

ὄντες8 of 17

being

G5607

being

ἐκ9 of 17

out of

G1537

a primary preposition denoting origin (the point whence action or motion proceeds), from, out (of place, time, or cause literal or figurative; direct

γὰρ10 of 17

for

G1063

properly, assigning a reason (used in argument, explanation or intensification; often with other particles)

τοῦ11 of 17
G3588

the (sometimes to be supplied, at others omitted, in english idiom)

περισσεύματος12 of 17

the abundance

G4051

a surplus, or superabundance

τῆς13 of 17
G3588

the (sometimes to be supplied, at others omitted, in english idiom)

καρδίας14 of 17

of the heart

G2588

the heart, i.e., (figuratively) the thoughts or feelings (mind); also (by analogy) the middle

τὸ15 of 17
G3588

the (sometimes to be supplied, at others omitted, in english idiom)

στόμα16 of 17

the mouth

G4750

the mouth (as if a gash in the face); by implication, language (and its relations); figuratively, an opening (in the earth); specially, the front or e

λαλεῖ17 of 17

speak

G2980

to talk, i.e., utter words


Study Guide

Historical Context

This verse is found in the book of Matthew. Understanding the historical and cultural background helps illuminate its meaning for the original audience and for us today.

Theological Significance

Matthew 12:34 contributes to our understanding of God's character and His relationship with humanity. Consider how this verse connects to the broader themes of Scripture.

Cross-References

Verses related to Matthew 12:34 from Treasury of Scripture Knowledge

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