John 3:13

13. Ascended… came down. After the words ascended up to heaven, there is implied the clause, and so no man is able to testify. The words do not mean that the Son of man had then ascended. They deny that any man had. And so the Son of man, which came down from heaven, is the sole authoritative testifier. He alone is the sure witness.

Which is in heaven The Son of man needed not to ascend; for though on earth he is ever in heaven. See note on John 2:51. The person of the Son of man is again a Jacob’s ladder; though its feet are on earth its head is in heaven. The angels of God, that is, the revelations of God’s truth, can thus descend. And they descend with the absolute certainty of truth, because it is a living ladder, and its head has eyes that see things in heaven just as they are. The incarnate Son of man is the conductor from heaven to earth of all those divine facts and truths which the eternal Logos hath seen and known, and evermore will see and know, in his infallible unity with God. Now Nicodemus has first admitted, on the faith of miracles, that Jesus is sent from God; he is bound then to credit his declaration of his insight of heaven, and accept the highest mysteries, even of regeneration, etc.