Mark 13:32
32 But of that day and that hour knoweth no man, no, not the angels which are in heaven, neither the Son, but the Father.
Matthew 24:36
36 But of that day and hour knoweth no man, no, not the angels of heaven, but my Father only.
In Matthew 24 and Mark 13 - two parallel chapters describing the Great Tribulation - Christ says that no one, not even He, knew when His second coming would be. How is that possible, if Jesus is God?
While Jesus was on earth, He was fully human and fully divine - a doctrine formally called the Hypostatic Union. There wasn't a "man part" and a "God part" - they were perfectly merged in every single cell in Christ's body.
We know that He performed many miracles, knew people's thoughts (Matthew 9:3-4, Luke 11:17), and did a host of other things that exercised His deity, during the first advent.
On the other hand, we frequently see Christ praying to the Father, and in these prayers, asking for things (Luke 22:32, Matthew 26:39, etc.). We also see, in the description of His early life, Him gaining wisdom:
Luke 2:52
52 And Jesus increased in wisdom and stature, and in favour with God and man.
If Jesus was omniscient in the incarnation, the above would make no sense.
He also, of course, limited His omnipotence, almost every day of His life. He allowed himself to have to work, He allowed himself to be poor, and He allowed himself to be homeless. He allowed himself to be schemed against, imprisoned, tried, and finally, He allowed himself to die. The entire time, He could have stopped time, turned everyone inside out, put them back together again, and then teleport to North America. But He didn't do those things.
So, what can we conclude, by looking at the various details of Christ's ability in His incarnation? He had, for reasons known to Him, limited His ability in the incarnation, in certain ways, which were in accordance with His will, and the Father's will. One of those elements was not knowing the date of His second coming.
The following passages explicitly speak of the operation of Christ limiting himself during the incarnation:
Philippians 2:5-8
5 Let this mind be in you, which was also in Christ Jesus:
6 Who, being in the form of God, thought it not robbery to be equal with God:
7 But made himself of no reputation, and took upon him the form of a servant, and was made in the likeness of men:
8 And being found in fashion as a man, he humbled himself, and became obedient unto death, even the death of the cross.
Hebrews 2:9
9 But we see Jesus, who was made a little lower than the angels for the suffering of death, crowned with glory and honour; that he by the grace of God should taste death for every man.
Notice that both of the above mention Christ's death. Christ allowing himself to die (John 10:18) is no more or less uncharacteristic of God than limiting His knowledge. He didn't have to allow himself to die, and didn't have to limit His knowledge. All of these things are elements of the incarnation.
Why specifically didn't He allow himself to know the date of His second coming, during the incarnation? While no one can say for sure, this is likely just an instance of Christ emphasizing His humanity. The precise reason is never given in Scripture, so anyone who says that they know is making an educated guess, at best. However, the idea that this somehow assaults His deity makes no sense, given how Christ limited himself in other ways during His short life here on earth.