Catena Aurea on John 3:31–32: Augustine of Hippo

Or, speaketh of the earth, he saith of the man, i. e. of himself, so far as he speaks merely humanly. If he says ought divine, he is enlightened by God to say it: as saith the Apostle; Yet not I, but the grace of God which was with me. (1 Cor. 15:10) John then, so far as pertains to John, is of the earth, and speaketh of the earth: if ye hear ought divine from him, attribute it to the Enlightener, not to him who hath received the light.