It would be worthy of your diligence to set the phrases of the Gospel side by side, and compare together those of Matthew and those of Mark, for these two alone are found in concurrence in this passage. The wording of Matthew is “of that day and hour knoweth no man, no, not the angels of heaven, but my Father only.” That of Mark runs, “But of that day and that hour knoweth no man, no, not the angels which are in heaven, neither the Son, but the Father.” What is noticeable in these passages is this; that Matthew says nothing about the ignorance of the Son, and seems to agree with Mark as to sense in saying “but my Father only.” Now I understand the word “only” to have been used in contradistinction to the angels, but that the Son is not included with His own servants in ignorance.
He could not say what is false Who said “All things that the Father hath are Mine,” but one of the things which the Father hath is knowledge of that day and of that hour. In the passage in Matthew, then, the Lord made no mention of His own Person, as a matter beyond controversy, and said that the angels knew not and that His Father alone knew, tacitly asserting the knowledge of His Father to be His own knowledge too, because of what He had said elsewhere, “as the Father knoweth me even so know I the Father,”and if the Father has complete knowledge of the Son, nothing excepted, so that He knows all knowledge to dwell in Him, He will clearly be known as fully by the Son with all His inherent wisdom and all His knowledge of things to come. This modification, I think, may be given to the words of Matthew, “but my Father only.” Now as to the words of Mark, who appears distinctly to exclude the Son from the knowledge, my opinion is this. No man knoweth, neither the angels of God; nor yet the Son would have known unless the Father had known: that is, the cause of the Son’s knowing comes from the Father. To a fair hearer there is no violence in this interpretation, because the word “only” is not added as it is in Matthew. Mark’s sense, then, is as follows: of that day and of that hour knoweth no man, nor the angels of God; but even the Son would not have known if the Father had not known, for the knowledge naturally His was given by the Father. This is very decorous and becoming the divine nature to say of the Son, because He has, His knowledge and His being, beheld in all the wisdom and glory which become His Godhead, from Him with Whom He is consubstantial.
Their tenth objection is the ignorance, and the statement that Of the last day and hour knoweth no man, not even the Son Himself, but the Father. And yet how can Wisdom be ignorant of anything—that is, Wisdom Who made the worlds, Who perfects them, Who remodels them, Who is the Limit of all things that were made, Who knoweth the things of God as the spirit of a man knows the things that are in him? For what can be more perfect than this knowledge? How then can you say that all things before that hour He knows accurately, and all things that are to happen about the time of the end, but of the hour itself He is ignorant? For such a thing would be like a riddle; as if one were to say that he knew accurately all that was in front of the wall, but did not know the wall itself; or that, knowing the end of the day, he did not know the beginning of the night—where knowledge of the one necessarily brings in the other. Thus everyone must see that He knows as God, and knows not as Man;—if one may separate the visible from that which is discerned by thought alone. For the absolute and unconditioned use of the Name “The Son” in this passage, without the addition of whose Son, gives us this thought, that we are to understand the ignorance in the most reverent sense, by attributing it to the Manhood, and not to the Godhead.
St Gregory Nazianzen the Theologian (Doctor of the Church), Oration XXX
Source:
ccel.org/ccel/schaff/npnf207.iii.xvi.html