Someone may ask how can I trust the Quran and it is revelead after Jesus by 600 years?

600 years are irrelevant because God sends prophets at times when humanity most needs correction or renewal. Just as the Torah spanned centuries from Moses to the later prophets, and the Gospel built upon them, the Quran arrives as the final, universal confirmation of all previous revelations. There are thousands of years between Moses and Jesus (peace be upon them).

So God can send prophets at anytime when humanity most needs correction also, the "source" of the Quran is "Prophet Muhammad" through revelation from God to him, and Jesus is not the source of the Quran so the time between them is irrelevant.