Is it normal to believe in a god but not have a religion?

I never thought about that. He talked of his father in heaven but never spoke of a religious sect. There was the Jewish religion and several Roman gods but the Romans did not have a specific religion. Christianity came into being 300 years after Christ's death. Islam was founded at the start of the 7th century but modern Islam did not exist until the Islam prophet Mohammed wrote the Quran starting in 609 and finished in 632. He said he was receiving revelations from the angel Gabriel. The Quran is heavily based on the Old Testement and some from the New Testament where Jesus is mentioned several times and is even regarded as a prophet.