Mohammed went alone into a cave and later came out claiming the angel "Gabriel" had chatted with him and had told him to dictate their conversation to others to write down, and it became known as the Koran.
By contrast, the arrival of Jesus 600 years before was foretold multiple time by the Old T prophets, which make his credentials far more weighty..
OLD TESTAMENT FORETOLD JESUS'S ARRIVAL
The Messiah would be born in Bethlehem - fulfilled
"But you, Bethlehem Ephrathah, though you are small among the clans of Judah, out of you will come for me one who will be ruler over Israel, whose origins are from of old, from ancient times." (Micah 5:2)
The Messiah would enter Jerusalem on a donkey - fulfilled
"Shout, Daughter of Jerusalem! See, your king comes to you, righteous and having salvation, gentle and riding on a donkey, on a colt, the foal of a donkey" (Zech 9:9)
The Messiah would be silent before His accusers - fulfilled
"He was oppressed and afflicted, yet he did not open his mouth; he was led like a lamb to the slaughter, and as a sheep before her shearers is silent, so he did not open his mouth" (Isaiah 53:7).
The Messiah would be flogged and spit on - fulfilled
"I offered my back to those who beat me, my cheeks to those who pulled out my beard, I did not hide my face from mocking and spitting" (Isaiah 50:6)
The Messiah would suffer nails and spearthrust - fulfilled
".. he was pierced for our transgressions, he was crushed for our iniquities; the punishment that brought us peace was upon him, and by his wounds we are healed" (Isaiah 53:5)
The Messiah would be crucified with thieves - fulfilled
"..he poured out his life unto death, and was numbered with the transgressors. For he bore the sin of many, and made intercession for the transgressors" (Isaiah 53:12)
The betrayal money would be thrown in the temple for a potters field - fulfilled
"Throw it to the potter- the handsome price at which they priced me. So I took the thirty pieces of silver and threw them into the house of the Lord to the potter" (Zech 11:13)