I know a few Muslims. Even have some good friends that are Muslims (a family).
They helped me out when times were especially tough and few would help.
That being said, I once quoted some stuff to my friend. He told me that it wasn’t in the Koran. I said, that’s correct, I am quoting other books.
I wrote chapter and verse down, on a piece of paper, for him to read later. I told him, use any legitimate Islamic source for that.
A week later, saw him again. He told me he looked the verses up and they said exactly what I told him they said.
I said, I know. I used Islamic sources myself.