John Calvin Commentary John 3:32

"What he hath seen and heard, of that he beareth witness; and no man receiveth his witness." — John 3:32 (ASV)

And what he hath seen and heard. John continues in his duty; for, in order to gain disciples for Christ, he presents Christ’s teaching as certain, because he speaks nothing but what he has received from the Father. Seeing and hearing are contrasted with doubtful opinions, unfounded rumors, and every kind of falsehood. For he means that Christ teaches nothing but what has been fully confirmed. But someone will say that little credit is due to one who has nothing but what he has heard. I reply, this phrase signifies that Christ has been taught by the Father, so that he brings forward nothing but what is divine—or, in other words, what has been revealed to him by God.

Now this pertains to the whole person of Christ, insofar as the Father sent him into the world as His ambassador and interpreter. He afterwards charges the world with ingratitude, for basely and wickedly rejecting such an undoubted and faithful interpreter of God. In this way he counters the offense that might cause many to turn away from the faith, and might hinder or slow the progress of many. For, as we are accustomed to depend too much on the judgment of the world, a considerable number of people judge the Gospel by the world's contempt for it, or at least, when they see it everywhere rejected, they are prejudiced by that event and are made more unwilling and slower to believe.

Therefore, whenever we see such obstinacy in the world, let this admonition keep us in constant obedience to the Gospel: namely, that it is truth that came from God. When he says that NO-MAN receiveth his testimony, he means that there are very few and almost no believers when compared with the vast crowd of unbelievers.