In the Name of God, the Merciful, the Compassionate.
The Messenger believes in what has been revealed to him from his Sustainer. As do the men of faith. Each one [of them] believes in God, His angels, His Books, and His Messengers. “We make no distinction [they say] between one and another of His Messengers...” [to the end of the verse]1
An awesome question and a state of mind arising from the unfolding of a vast Divine bounty were the causes of my explaining a universal, lengthy point about this comprehensive, elevated and sublime verse. It was like this: it occurred to my spirit: why does one who denies a part of the truths of belief become a disbeliever, and one who does not accept a part of them cannot be a Muslim? Surely belief in God and the hereafter dispels the darkness like the sun. Also, why does a person who denies one of the pillars and truths of belief become an apostate, falling into disbelief, and by not accepting it, quit Islam? Whereas if he believes in the other pillars of belief, it should save him from absolute disbelief?
T h e A n s w e r : Belief is a single truth, which, composed of its six pillars, cannot be divided up. It is a universal that cannot be separated into parts. It is a whole that cannot be broken up. For each of the pillars of belief proves the other pillars with the proofs that prove itself. They are all extremely powerful proofs of each other. In which case, an invalid idea that cannot shake all the pillars together with all their proofs, cannot in reality negate any one of the pillars, or even a single of their truths, and cannot deny them. Under the veil of non-acceptance one might only, by shutting his eyes, commit ‘obstinate unbelief;’ he would by degrees fall into absolute disbelief and lose his humanity, and go to Hell, both physically and mentally. In this station then, with God’s grace, we shall explain this supreme matter in six Points in the form of brief summaries, just as in the Fruits Of Belief when proving the resurrection of the dead, the other pillars of belief’s proofs of resurrection were propounded in the form of brief summaries.
Qur’an, 2:285.