Was Jesus omniscient when he said "But of that day and hour no one knows, not even the angels in heaven, nor the Son, but the Father alone?" (Mathew 24:36 NASB 1995)
This question examines whether Jesus was all knowing in his humanity, while at the same time not knowing the exact time of his return.
This question is almost the same as asking about Mark 2:8 and whether it should read:
And immediately, Jesus having known in His spirit that ...
or
And immediately, Jesus having known by His Spirit [ie, the Holy Spirit] that ...
The first implies omniscience and the second implies dependence on the enlightenment of the Holy Spirit for humanly inaccessible information. [Spoiler alert: I am inclined to the latter view for reasons to be explained shortly.]
Whatever, Matt 24:36 teaches, it shows that Jesus, at least during His incarnation was NOT omniscient. Indeed, as many have correctly pointed out, Jesus appeared to be anything but divine:
All this was by the design and voluntary submission of Christ:
Phil 2:5-8 - Christ Jesus: Who, existing in the form of God, did not consider equality with God something to be grasped, but emptied Himself, taking the form of a servant, being made in human likeness. And being found in appearance as a man, He humbled Himself and became obedient to death—even death on a cross.
That is, Jesus voluntarily laid aside His divine privileges to become temporarily human as Hebrews explains:
Heb 2:8, 9, 17, 18 When God subjected all things to him, He left nothing outside of his control. Yet at present we do not see everything subject to him. 9 But we see Jesus, who was made a little lower than the angels, now crowned with glory and honor because He suffered death, so that by the grace of God He might taste death for everyone.
17 For this reason He had to be made like His brothers in every way, so that He might become a merciful and faithful high priest in service to God, in order to make atonement for the sins of the people. 18 Because He Himself suffered when He was tempted, He is able to help those who are being tempted.
The fact that Jesus laid aside divine powers and privileges, does not mean they were alienated from Him - that was the great temptation, far greater that we would ever experience, of having access to infinite power but voluntarily not using it. Indeed, Jesus was still God as the Gospels observe, Matt 1:23, John 1:1, 18, 5:17, 18, 23, 8:58, 10:30, John 20:28, etc.
Was Jesus omniscient?
We are not told he was. Only by reading-in presumptions from post Apostolic writings can this idea have any credence. But as we are to have a Biblical and Hermeneutic focus here, that kind of unsanctioned reasoning is theological in nature and should be dismissed.
Clearly Jesus is doing one of two things here.
But about that day or hour no one knows, not even the angels in heaven, nor the Son, but only the Father. Matt 24:36
He committed no sin, and no deceit was found in his mouth. 1Peter 2:22
Knowing that, and simply believing that statement as we should, we can rule out #2
Jesus was not Omniscient, he did not know the details (time) of his return - only that he would. He was not privy to know all the details of God's plan and quite explicitly we are told that he did not know this detail.
whether Jesus was all knowing in his humanity
Jesus, the 'last Adam' was a man and we are told nothing about him being anymore than a man - except being without sin! So as explained earlier - Jesus didn't know at any time in any way unless we read-in our own assumptions based on traditional theology.
Jesus is not the Father and even the Holy Spirit does not know - assuming of course there is a Holy Spirit separate from the one true God 'the Father' that Jesus and Paul have affirmed.
Jesus spoke these things; and raising his eyes to heaven, he said, “Father,...3And this is eternal life, that they may know You, the only true God, and Jesus Christ whom You have sent.
...there is but one God, the Father, from whom all things came... 1Cor 8:6
I concur with Dottard that, Jesus voluntarily laid aside His divine privileges but not the imagined to become temporarily human. Which again, is a theological idea without scripture to support. Much like he totally gave up his divinity as noted in Ray's comments.
One can only wonder why we need to impose such strange ideas onto (holy) scripture and then claim it says what is does not.
"As the Father knows Me, so I know the Father" (John 10:15), and how does the Father know the Son, entirely or partially? Of course entirely. That means that also the Son knows the Father entirely and exactly that's why He is the Mediator through whom we can know or "come to" the Father (John 14:6), and that's why the Father is the Mediator through whom we can know or "come to" the Son, Jesus Christ (John 6:44). The same equality of knowledge is asserted by Matthew 11:27, that nobody knows the Son save the Father and vice versa. Yes, in this divine eternal infinite reciprocal life that "predated" (if even such a time-infected word is inadequate for this eternal life) the creation of the world Both Father and the Son knew Each-Other in entirety, with no need of mediation in the manner creatures are in need of it as mentioned above.
This being established, we come to impossibility that the Lord Jesus Christ did not know such a trifle as His own Second Coming. Indeed, He knows future without any prayers for accessing this knowledge, but in a sovereign, authoritative way, saying plainly that He will be killed and rise in the third day (Luke 9:22), He knows that Judas and Peter will betray Him predicting those treasons in minute detail, He knows that Jerusalem will not accept Him and that's why it will be razed by Romans (Matthew 23:35), He knows exactly by what kind of death Peter would glorify Him (John 21:18) and also James and John (Matthew 20:22) (just consider how outlandishly stupid it is to think that He knows the future of others while being ignorant of His own future of which an aspect is His second coming and the end of history!); moreover, He knows that the limited and imperfect understanding of His words by His disciples will start to be healed by their acceptance of the Holy Spirit, whom, He predicts that Father will send to them through His intercession (John 13:7 and 14:16), and this Holy Spirit also knows the "depths of God", that is to say, the entire depth of God the Father (1 Cor. 2:10), and the Lord Jesus Christ has this Spirit in Him infinitely (John 3:34), and if so, then with all the knowledge the Spirit has, which includes the entire knowledge of the Father's depths.
If so, then how on earth could He, the Lord Jesus Christ not know such a trifle as His own second coming? Does not He separate Himself from the ignorance of the people His own knowledge of the Second Coming in Acts 1:7? And, moreover, when He promises that "I am with you until the world ends" (Matthew 28:20) does not it clearly entail that He knows that world will end and when it will end?
And the final and most important point: Second Coming is a historical event. Now, what is more principal a thing, a historical event or God's will? Which depends on which? Of course it is a plain blasphemy and idolatry to say to say that God's will depends on a historical event, for then not God is God but History - with capital letters - is real God. Now, if it is excluded and if it is God's voluntary decision when to end history, then can at all the Father will to end the history through the Second Parousia of His Son without the Latter co-willing? Impossible! It would be the same as to say that even though the Father created the world through or together with His Logos (John 1:1-3), still the Logos did not know in eternity that Father was intending to create the world: suddenly Father pinched His co-eternal Son who was eternally with Him saying: "wake up, I contrived a wonderful thing until you languished idly in your mellow drowsiness, let us create the world!" And the Son asked: "What the heck is it? Explain to Me, Dad!" "Well, the sun, the stars, mountains, Homer, Shakespeare... let us start and I will explain to you in the process, it will be wonderful!" - But it is stupid to think such mythological scenes, for the divine will and knowledge of the Father and the Son is completely identical. Thus, no historical event can ever happen without God-the-Father willing or permitting it, and He can do so only with the God-the-Son co-willing and co-permitting and co-knowing for that matter.
Thus, the Lord Jesus Christ knows, just as the Father and the Spirit know, but why does He say that "neither Son, but Father alone" (Matthew 24:37) is a separate issue, and indeed this phrase should be more correctly translated "neither the Son [would know], if not the Father [had given Him this knowledge]" - οὐδὲ ὁ υἱός, εἰ μὴ ὁ πατὴρ μόνος. But I will not dwell on this any longer, for the OP question has been already dealt with sufficiently.
