What does it mean that Jesus is really human?
We Christians believe, of course, that God the Son is the Word made Flesh. That is, he is not just fully God, but fully human with a fully human body, soul, mind, and will.
Many weird paradoxes flow from this. For instance, since the “human soul that the Son of God assumed is endowed with a true human knowledge”, it follows that “this knowledge could not in itself be unlimited: it was exercised in the historical conditions of his existence in space and time.” (CCC 472).
So the gospels tell us that Jesus “increased in wisdom and in stature, and in favour with God and man” (Luke 2:52). He had to learn things like the rest of us. He needed to ask questions to get information he did not have. He had to stumble along making mistakes like every other kid learning a game or studying a trade or practicing his times tables. He really and truly “emptied himself” (Philippians 2:7).
Yet, mind-blowingly, the reason the omniscient God assumes a human nature with a human mind is precisely so that “’this truly human knowledge of God’s Son expressed the divine life of his person’” (CCC 473).
This is displayed in a strange paradox. On the one hand:
“The human nature of God’s Son, not by itself but by its union with the Word, knew and showed forth in itself everything that pertains to God” … Such is first of all the case with the intimate and immediate knowledge that the Son of God made man has of his Father….The Son in his human knowledge also showed the divine penetration he had into the secret thoughts of human hearts (Cf. Mark 2:8; John 2:25; 6:61; etc.).” (CCC 473)
So when it is necessary for the sake of revealing God to us, Jesus’ human knowledge, in union with his omniscience as God is enabled to possess knowledge in a supernatural way. That is why we see him display prophetic foreknowledge, such as when he tells Nathanael that he saw him under the fig tree before they ever met (cf. John 1:48).
He foretells his own Crucifixion and Resurrection to his disciples, predicts the betrayal by Judas and triple denial by Peter, prophecies the destruction of the temple and the city of Jerusalem, knows of the death of Lazarus before he is told of it, and can read the minds and hearts of strangers.
But in other moments, he himself freely confesses ignorance, most famously when he tells his disciples, concerning the Day of Judgment, “But of that day and hour no one knows, not even the angels of heaven, nor the Son, but the Father only” (Matthew 24:36). How to understand this mysterious combination of omniscience and ignorance? The Catechism tells us:
“By its union to the divine wisdom in the person of the Word incarnate, Christ enjoyed in his human knowledge the fullness of understanding of the eternal plans he had come to reveal….What he admitted to not knowing in this area, he elsewhere declared himself not sent to reveal.” (CCC 474)
In other words, his very ignorance is revelatory. The knowledge denied him is knowledge we do not need to have. He, like we, has to live by trust in his Father, especially when the blackness closes in and he must ask the most terrible question the human soul can ask: “My God! My God! Why have you forsaken me?” (Matthew 27:46). He has plumbed the depths of abandonment experienced by the worst sinner so that the worst sinner can receive his mercy. As the Catechism puts it (CCC 470), “In his soul as in his body, Christ thus expresses humanly the divine ways of the Trinity.”
This is not mere “angels dancing on pinheads” stuff. What it means is that Jesus really was “made like his brethren in every respect, so that he might become a merciful and faithful high priest in the service of God, to make expiation for the sins of the people. For because he himself has suffered and been tempted, he is able to help those who are tempted” (Hebrews 2:17-18).