Surah 27. An-Naml, Ayah 65

In this context, the term al-ghayb - rendered by me here as "the hidden reality" - apparently relates to the "how" of God's Being, the ultimate reality underlying the observable aspects of the universe, and the meaning and purpose inherent in its creation. My repetition, within brackets, of the words "none knows it", i.e., save God, is necessitated by the fact that He is infinite, unlimited as to space, and cannot, therefore, be included among the beings "in the heavens or on earth" who have all been created by Him.

The existence of Allah is certain. But nothing else can be known with certainty to our knowledge. He has told us of the Hereafter, and therefore we know it is true. But those who do not believe in Allah,-what knowledge or certainty can they have? Even when it is actually coming, they will not have the sense to perceive it.