But concerning that day and hour no one knows, not even the angels in heaven, nor the Son, but the Father only. (Matthew 24:36 ESV)
These are Jesus’ own words describing the time of His return. He speaks of Himself (the Son) as not knowing the hour it will take place. How can this statement be explained? If Jesus is God, how could He have not known the timing of His second coming?
I think the best explanation is to take Jesus’ statement at face value. At that moment He spoke those words He did not know the hour of His return. So how could that be? The answer is found in the self-limitation that took place when Christ emptied Himself to become man (Phil 2:6-7). He did not give up any of His deity – He still possessed His 100% divine nature. And that divine nature was still omniscient (all-knowing). But He did give up the independent use of His divine attributes. He did not always exercise the full use of His deity.
God the Son subjected Himself to the limitations of a human nature. In the mystery of this union of two natures, Jesus Christ’s thoughts and actions can be described at any given time as coming primarily through one nature or the other. For example, He did act through His divine nature on several occasions such as miracles (Matt 8:26-27; Luke 7:14-15)) and knowledge (John 1:47; 4:16-19). But there were other times when Jesus clearly set aside the use of His deity and functioned primarily through the limitations of His humanity: growth and development (Luke 2:40, 52), physical weariness (John 4:6), and learning of obedience (Heb 5:8). Yet, He was still perfect in His humanity.
Thus the answer to the ignorance of Jesus as to the hour of His return is found in His human nature. While His divine nature knew all things including the timing of His second coming, it was not revealed to the human consciousness of Jesus at that moment in Matthew 24:36. He was speaking at that moment through His self-limited human nature. He was not independently using His divine omniscience at that time.
In my opinion this is the best explanation as to how Jesus did not know the hour of His second coming. This view is not without its drawbacks. For another explanation of Matthew 24:36 that finds weakness with this view and offers a different interpretation see this link.
Jesus was and is one person with two natures. The great mystery is how He expressed those natures at various times. Scripture reveals some answers for us. But the union of the divine and human in Christ will never be fully known. Yet, there is no mystery as to what Christ Jesus accomplished as the God-man for us:
For there is one God, and there is one mediator between God and men, the man Christ Jesus, who gave himself as a ransom for all… (1 Tim 2:5-6)