Book of Allah, the Holy Quran. Allah Almighty has sent three holy books for the guidance of mankind through his chosen messengers before Prophet Muhammad (may peace be upon him). Prophet Dawood (David, peace be upon him) was the first to receive a holy book from Allah we know as “Zaboor”. The second holy book Tawrau (Torah) was sent through Prophet Musa (Moses, may peace be upon him) and the Injeel (Gospel) of Isa (Jesus, may peace be upon him).
After about six hundred years of the revelation of Injeel, the fourth and final holy book “Quran” was revealed on Prophet Muhammad (may peace be upon him) which not only encompasses the acknowledgment of earlier three holy books but also contains references contained in the earlier books. Therefore it is incumbent upon all Muslims to believe in all previous prophets and the three holy books sent on to mankind.