Although He was fully God as well as fully man (John 1:1, 14), Christ voluntarily restricted His use of certain divine attributes when He became flesh. “Although He existed in the form of God, [He] did not regard equality with God a thing to be grasped,” that is, to be held onto during His humanness (Phil. 2:6). It was not that He lost any divine attributes but that He voluntarily laid aside the use of some of them and would not manifest those attributes except as directed by His Father (John 4:34; 5:30; 6:38).
Jesus demonstrated His divine omniscience on many occasions. “He did not need anyone to bear witness concerning man for He Himself knew what was in man” (John 2:25). When, for example, Nicodemus came to Him at night, Jesus already knew what he was thinking and answered his question before it was asked (John 3:13).
But there were certain self-imposed restrictions in His human knowledge. He told the disciples, “All things that I have heard from My Father I have made known to you” (John 15:15). Jesus obediently restricted His knowledge to those things that the Father wanted Him to know during His earthly days of humanity. The Father revealed certain things to the Son as He reveals them to all men-through the Scripture, through the Father’s working in and through His life, and through the physical manifestations of God’s power and glory (see Rom. 1:19–20). Jesus learned much of His earthly knowledge just as every human being learns, and it is for that reason that He was able to keep “increasing in wisdom” (Luke 2:52). In addition to those ways, some truths were revealed to the Son directly by the Father. But in every case Jesus’ human knowledge was limited to what His heavenly Father provided.
Therefore, even on this last day before His arrest, the Son did not know the precise day and hour He would return to earth at His second coming. During Christ’s incarnation, the Father alone exercised unrestricted divine omniscience.
It seems probable that Christ regained full divine knowledge after the resurrection, as implied in His introduction to the Great Commission: “All authority has been given to Me in heaven and on earth” (Matt. 28:18). Just prior to His ascension, He told the disciples, “It is not for you to know times or epochs which the Father has fixed by His own authority” (Acts 1:7). He repeats the truth that the disciples would not be told the time of His appearing, but He did not exclude His own knowledge, as He did in the Olivet discourse.