Belief in the Koran
Allah has given humankind six foundations of faith to keep them on the right path. Perhaps the most critical of those beliefs is the belief in the Koran. Why? Because, quite plainly, if you lose your faith in the Koran, your faith in any or all of the other pillars will be shaken. It is the Koran that states what the other pillars are, and it is the Koran that presents their existence as a matter of fact. In other words, if you don't believe in the Koran, how can you believe what it says about the Creator, the angels, or the afterlife?
According to the Koran, a Muslim must believe the entire Koran, not just parts of it. Doubting any part of it is like doubting the whole volume. The same rule applies: all or none at all. Once a Muslim embraces the Six Pillars of Faith, he or she can begin practicing the faith that Allah teaches in His Holy Book.