Question: "If Jesus is God, why did He not know when He would return?"
Answer: Speaking of His second coming, Jesus said, “No one knows about that day or hour, not even the angels in heaven, nor the Son, but only the Father” (Matthew 24:36; cf. Mark 13:32). The Bible clearly teaches that Jesus is God (John 1:1, 14), and we know that God is omniscient. So it seems strange that Jesus would say that He did not know when He would return.
The key to understanding Jesus’ seeming lack of knowledge in this matter lies in the nature of the Incarnation. When the Son of God became a man, He remained fully God, but He also took on a true human nature. Jesus retained all the attributes of divinity, yet, as a man, He voluntarily restricted their use. This was part of the “self-emptying” or self-renunciation spoken of in Philippians 2:6–8. When Christ entered our world, He laid aside the privileges that had been His in heaven. Rather than stay on His throne in heaven, Jesus “made himself nothing” (as the NIV translates Philippians 2:7). When He came to earth, “he gave up his divine privileges” (NLT). He veiled His glory, and He chose to occupy the position of a servant.
There were times when Jesus publicly manifested His divine knowledge and power on earth (John 2:25; 11:43 –44). On those occasions, Jesus’ demonstrations of His divinity were directed by the Father. On other occasions, He had no such directive from the Father, and He kept His glory veiled. On all occasions, Jesus obeyed the Father’s will: “I always do what pleases him,” He said (John 8:29).
So, when Jesus said He did not know when He would return, He was actively humbling Himself and taking the form of a servant (see Philippians 2:7–8). Since no other mortal knows the time of Jesus’ return—that information is the Father’s alone (Matthew 24:36)—Jesus voluntarily restricted His knowledge on that point. It was part of Jesus’ submission to the Father (see John 5:30; 6:38; 8:28–29) and His mission to live a human life.
Some things Jesus apparently chose to “give up the rights” to be privy to during His earthly ministry. The knowledge of when He would return was one of those things. Jesus, now exalted in heaven, surely knows all, including the timing of His second coming.