John Calvin Commentary Matthew 12:34

"Ye offspring of vipers, how can ye, being evil, speak good things? for out of the abundance of the heart the mouth speaketh." — Matthew 12:34 (ASV)

Offspring of vipers. The similarity between the tree and the fruit is here applied by Christ to nothing more than speech, because this provided an opportunity to detect the inner and hidden malice of the scribes; and that is the reason why he focuses so much on this one kind of sin. It is because their falsehood and slanders revealed what was not as visible in the rest of their life, that Christ attacks them with such severity. “There is no reason to wonder,” he says, “that you vomit out wicked words; for your heart is full of malice.”

Nor should we suppose that he should have treated them more gently, because some might consider this rebuke excessively severe. There are other sins, no doubt, that call for harsh rebukes; but when hypocritical people distort what is right, or falsely portray what is sinful, such wickedness makes it necessary for God to thunder against it in a more terrible manner than against other sins.

Now Christ's purpose, suggested by this event, was to condemn the wicked sophistry that turns light into darkness. This passage shows how highly valuable truth is in the sight of the Lord, since he maintains and defends it with such rigor. If only this were earnestly considered by those people whose ingenuity is too readily employed in defending any cause, and whose corruptible tongue disguises deceptions!

In a particular way, Christ grows angry with those whom ambition, or envy, or some other fraudulent design, prompts to slander, even when there is nothing their conscience condemns. Against the Pharisees, too, as was his custom, Christ used greater harshness, because they were so captivated by an unfounded conviction of their own righteousness that an ordinary warning had no effect on them. And until hypocrites are sharply pierced,¹³⁶ all that is said to them is treated with scorn and contempt.

How can you speak what is good? We have previously hinted that proverbial sayings should not be rigidly interpreted as an invariable rule, for they state nothing more than the ordinary fact. Sometimes, no doubt, a cruel man will deceive the simple with honeyed flatteries, a cunning man will cheat under the guise of simplicity, and a man of very wicked thoughts will express almost angelic purity of language.¹³⁷

But the ordinary practice demonstrates the truth of what Christ here says, that out of the abundance of the heart the mouth speaketh; in agreement with the old proverb, which declared the tongue to be the index of the mind.¹³⁸ And, indeed, whatever hidden and crooked recesses may exist in the human heart, and whatever may be the amazing schemes by which everyone conceals their vices, yet the Lord extorts from each of them some kind of confession, so that they reveal by their tongue their natural disposition and hidden feelings.

We must also observe the purpose for which Christ uses these parables; for he reproaches the Pharisees with having manifested by words the malice which they had inwardly conceived. Besides, knowing them to be sworn enemies, he takes occasion from a single slander to destroy their credibility with the people, which gave them too much influence in deceiving and in doing harm.

Though good speeches do not always proceed from the innermost heart, but originate (as the saying goes) on the tip of the tongue, yet it is an invariable truth that bad speeches are indications of a bad heart.

¹³⁶ “Iusques a ce qu’ils sentent qu’on le poigne a bon escient;” — “till they feel that they are pierced in good earnest.”;” — “till they feel that they are pierced in good earnest.”

¹³⁷ “Il semblera, a l’ouir parler, qu’il ait une purete Angelique;” — “to hear him speak, you would imagine that he has the purity of an Angel.”;” — “to hear him speak, you would imagine that he has the purity of an Angel.”

¹³⁸ “Comme aussi le proverbe ancien portoit, Que la langue est le charactere ou pourtrait du coeur;” — “as also the old proverb bore, That the tongue is the type or portrait of the heart.”;” — “as also the old proverb bore, That the tongue is the type or portrait of the heart.”