Tafsir of Yunus 10:6

"Indeed, in the alternation of the night and the day": Another general reminder regarding what was mentioned. That is, in their succession and the fact that each of them follows the other, for this necessitates the movement of all the spheres and the stars within them—according to what has preceded—while the earth remains stationary; this being the case in most locations. As for the latitude of ninety degrees, nothing rises or sets through that movement at all, but rather through other movements. Similarly, in areas near to it, rising and setting may occur through means other than that. This movement is called the "daily movement." Some have attributed it entirely to the earth, while others have attributed part of it to the earth and part to the greatest sphere. It is well-known among many of the later scholars that the sun itself travels, subjected by the command of Allah Almighty, in a contained sea, rising and setting wherever Allah Almighty wills, and there is no movement for the sky; a view which the Greatest Sheikh—may his secret be sanctified—also held.

It is also permissible that by "the alternation of the night and the day," is meant their variation in themselves, by the increase of one through the decrease of the other, and the decrease of one through the increase of the other. According to them, this arises from the varying state of the sun in relation to us—in proximity and distance—due to its second movement, by which the seasons vary and the year is divided into intervals. The night and day may be equal in some times for some, and this only occurs if the sun happens to reach the equinoctial point at sunrise or sunset, and if the apogee is at one of the equinoxes. For if the first is realized, the arc of the day is like the arc of the night, and if the second is realized, the matter is the opposite. This is very rare and is not possible according to what Ptolemy held regarding the immobility of the apogee; thus, for him, the night and day never truly equalize.

It may also mean their difference according to location. As for length and shortness, the lands close to the North Pole have summer days that are longer and summer nights that are shorter than the days and nights of lands far from it. As for them in themselves, the sphericity of the earth, as they state, necessitates that at certain times it is night in some places and day in the corresponding parts opposite them.

"And [in] what Allah has created in the heavens and the earth": of perfect fabrications and firm traces, "are signs": great and numerous, indicating the Messenger, the sending down of the Book, the clarification of the paths of guidance, and the identification of the precipices of destruction, "for a people who fear [Allah]": the Almighty, and beware of the consequence. He, Glory be to Him, specifically mentioned them because piety is what prompts one to look and contemplate.