The Quran (Koran) is the sacred book of what religion

The Quran (Koran) is the sacred book of Islam.

The Quran, also spelled as Koran, is the sacred book of the Islamic religion. It is considered the word of God as revealed to the Prophet Muhammad through the angel Gabriel. The Quran is regarded as the final and most important revelation in Islam, and it serves as a guide for Muslims in matters of faith, worship, and conduct.