PRO 30:4THE incarnation was no mere emanation of divinity, neither was it a Person once divine Who ceased to be so by becoming man... but One Who, to glorify the Father, and in accomplishment of the purposes of grace to the glory of God, took humanity into union with Godhead in His Person. Therefore it is that He could say, and of Him alone could it be said, " the Son of man Who is in heaven " (John 3:13), even as He is the Only-begotten Son Who is (not merely Who was) in the bosom of the Father (John 1:18).
He it is Who met, and more than met, the challenge of Agur (Prov. 30:4), speaking prophetically to Ithiel and Ucal, “Who hath ascended up into the heavens, and descended? Who hath gathered the wind in His fists? Who hath bound the waters in a mantle? Who hath established all the ends of the earth? What is His name, and what is His Son's name?-if thou knowest."
It is God, not man, Who can take up this challenge; but it is God become man-yea, the Son of man. For “no one has gone up into heaven save He Who came down out of heaven, the Son of man Who is in heaven." See also Eph. 4:8-10.
Exposition of the Gospel of John,