John Calvin Commentary 1 Corinthians 12:3

"Wherefore I make known unto you, that no man speaking in the Spirit of God saith, Jesus is anathema; and no man can say, Jesus is Lord, but in the Holy Spirit." — 1 Corinthians 12:3 (ASV)

Therefore I give you to know. Having admonished them from their own experience, he sets before them a general doctrine, which he deduces from it. For what the Corinthians had experienced in themselves is common to all humankind—to wander on in error, before they are brought back, through the kindness of God, into the way of truth.

Therefore, it is necessary that we should be directed by the Spirit of God, or we will wander on forever. From this, too, it follows that all things that relate to the true knowledge of God are the gifts of the Holy Spirit. He at the same time derives an argument from opposite causes to opposite effects.

No one, speaking by the Spirit of God, can revile Christ; so, on the other hand, no one can speak well of Christ, but by the Spirit of Christ. To say that Jesus is accursed is utter blasphemy against him. To say that Jesus is the Lord, is to speak of him in honorable terms and with reverence, and to extol his majesty.

Here it is asked: “As the wicked sometimes speak of Christ in honorable and magnificent terms, is this an indication that they have the Spirit of God?” I answer: “They undoubtedly have, so far as that effect is concerned; but the gift of regeneration is one thing, and the gift of bare intelligence, with which Judas himself was endowed, when he preached the gospel, is quite another.”

From this, also, we perceive how great our weakness is, as we cannot even move our tongue for the celebration of God’s praise, unless it is governed by his Spirit. Scripture also frequently reminds us of this, and the saints everywhere acknowledge that unless the Lord opens their mouths, they are not equipped to be the heralds of his praise. Among others, Isaiah says, I am a man of unclean lips (Isaiah 6:5).