[Genoa]

John 7:15 — “The Jews therefore marvelled, saying, How knoweth this man letters, having never learned?” This seems to indicate that Jesus was not formally trained. His followers called him Rabbi as a courtesy.

[Pan_Yans Wife]

Having the knowledge of God in His brain, what earthly training could possibly suit Him? Are you suggesting that He did not sound learned and that His understanding was not up to that of a Rabbi?

[Timotheous]

John 7 describes 2 crowd reactions to Jesus - that one was from people who had never heard him before + didn’t know about the plot to kill him - check it out. They go on to call him demonised - do you take that at face value too?
Nicodemus calls him Rabbi in Jn3 - since he was a sanhedrin member, he would seem a reliable witness...

[nonsporting]

John 7:15 — “The Jews therefore marveled, saying, How knoweth this man letters, having never learned?” This seems to indicate that Jesus was not formally trained. His followers called him Rabbi as a courtesy.

He was not trained by men. He is after all the Word of God.

They called him Rabbi because he was one who spoke with authority. "And they were astonished at his doctrine: for he taught them as one that had authority, and not as the scribes." Mark 1:22