The Jews therefore marveled, saying, “How is it that this man has learning,[d] when he has never studied?” So Jesus answered them, “My teaching is not mine, but His who sent me…” John 7:15-16
Jesus received His wisdom and knowledge by direct revelation from the Spirit of God rather than by the teachings of man. Jesus had been learning, but not through man. The Holy Ghost was His teacher. Jesus had to be taught the things of God. This looks contrary to Colossians 2:3, which says that all the treasures of wisdom and knowledge are hidden in Jesus. If Jesus was God manifest in the flesh, why would He have to learn or be taught?
The harmony between these apparently opposite statements is that Jesus’ spirit man was 100% God and had all of the wisdom and understanding of God in it, but it was manifest in natural flesh. It wasn’t sinful flesh but it was flesh, nonetheless, and had to be educated. Jesus was not taught by man, but He was taught by the direct revelation of the Holy Spirit. The knowledge was within Him but it had to be drawn out.
At the new birth, a born-again man’s spirit "is renewed in knowledge after the image of him that created him" (Col. 3:10). "We have the mind of Christ" (1 Cor. 2:16), and "an unction from the Holy One, and ye know all things" (1 Jn. 2:20). All of these things are a reality in our spiritual man. However, just as Jesus had to be taught, so we must draw this wisdom and knowledge out of our spirits and renew our minds with it (Rom. 12:2). This is one of the main ministries of the Holy Spirit to the believer. Through the new birth, we have received the mind of Christ in our spirit man and are in the process of growing in wisdom by drawing this knowledge out of our spirits and renewing (or reprogramming) our minds. This wisdom has to be drawn out by faith, time spent in the Word, and prayer.
[d] John 7:15 Or this man knows his letters