For indeed in the remembrance of God do hearts find rest.7
Through knowing a single Creator, all spirits and hearts are delivered from the distress and confusion arising from misguidance, and from the spiritual pains arising from distress. They are saved by attributing all beings to a single Maker. They find assurance through the remembrance of a single God. For, as is proved decisively in the Twenty-Second Word, if all beings are not attributed to a single being, it becomes necessary to ascribe a single thing to innumerable causes, and then the existence of a single thing becomes as difficult as all beings. For if attributed to God, innumerable things are ascribed to a single being, and if they are not attributed to Him, it becomes necessary to attribute everything to innumerable causes. Then a single fruit becomes as difficult as the universe, indeed, more difficult. For just as if the management of one soldier is given to a hundred different people, a hundred difficulties arise, and if a hundred soldiers are given to the direction of one officer, they are as easy to manage as a single soldier, so too the coinciding of numerous different causes in the creation of a single thing is difficult to the hundredth degree. And if the creation of numerous things is given to a single being, it becomes easy to the hundredth degree.
Thus, it is only by recognizing the Creator's unity and knowledge of God that man may be delivered from the boundless distress arising from the desire to search for the truth inherent in his nature. Since there are endless difficulties and pains in unbelief and associating partners with God, that way is certainly impossible and devoid of truth. While since suitably to the ease, abundance, and fine art in the creation of beings, there is a boundless ease in affirming Divine unity, that way is surely necessary and the truth.
O you miserable people of misguidance! See how dark and full of pain is the way of misguidance! What is it that makes you take it? And see how easy and pleasant is the way of belief and affirming Divine unity! Take that way and be delivered!
------------
7.Qur'an 13:28