John Calvin Commentary 1 Corinthians 1:6

"even as the testimony of Christ was confirmed in you:" — 1 Corinthians 1:6 (ASV)

Even as the testimony... Erasmus offers a different rendering, to this effect: “that by these things the testimony of Christ was confirmed in them;” that is, by knowledge and by the word. The words, however, convey another meaning, and if they are not distorted, the meaning is clear: that God has sealed the truth of His gospel among the Corinthians, to confirm it.

Now, this might be done in two ways: either by miracles or by the inward testimony of the Holy Spirit. Chrysostom seems to understand this as referring to miracles, but I understand it in a broader sense. First of all, it is certain that the gospel is properly confirmed in our experience by faith, because it is only when we receive it by faith that we set to our seal that God is true (John 3:33). And though I admit that miracles ought to carry weight in confirming it, yet we must look higher for the origin—namely, that the Spirit of God is the earnest and seal.

Accordingly, I explain these words in this way: that the Corinthians excelled in knowledge, since God had from the beginning made His gospel effective among them. This was not merely in one way, but by the internal influence of the Spirit, by the excellence and variety of gifts, by miracles, and by all other helps. He calls the gospel the testimony of Christ, or respecting Christ, because its entire substance tends to reveal Christ to us,

In whom all the treasures of knowledge are hid (Colossians 2:3).

If anyone prefers to take it in an active sense, on the ground that Christ is the primary author of the gospel, so that the Apostles were nothing but secondary or inferior witnesses, I will not strongly oppose it. I feel better satisfied, however, with the former exposition.

It is true that a little later (1 Corinthians 2:1), the testimony of God must, beyond all controversy, be taken in an active sense, as a passive meaning would not be at all suitable. Here, however, the case is different. Furthermore, that passage strengthens my view, as he immediately adds what this is: to know nothing but Christ (1 Corinthians 2:2).