Tafsir of Ya seen 36:38

"A resting place for it" means a temporary, predetermined limit at which it ends its course in its orbit at the end of the year.

It is likened to the resting place of a traveler when he completes his journey, or to the limit of its rising and setting points; for it traverses them, rising by rising and setting by setting, until it reaches its furthest point, then returns. That is its limit and its resting place, for it does not exceed it. Or, it refers to the limit of its daily journey as seen by our eyes, which is the sunset.

It is also said: Its resting place is its appointed time, which God has decreed for its course, so it comes to rest at the end of the year. Another view is that it is the time when it comes to rest and its motion ceases, which is the Day of Resurrection.

It is recited: (runs to a resting place for it). Ibn Mas‘ud recited: (no resting place for it), meaning: it continues to run and does not rest. It is also recited: (no resting place for it), where "no" (la) acts as a negation (meaning "there is not").

{That}—this running according to that precise estimation and calculation, which exhausts the intellects to extract and confuses understandings to deduce—is nothing but the decree of the One who is Overpowering in His ability over all that is decreed, and All-Encompassing in knowledge of all that is known.

{And the moon} is in the nominative case as an initial subject, or as a conjunction to "the night," meaning: "Among His signs is the moon." It is in the accusative case by a verb implied by "We have determined it."

There must be an implied genitive addition in {We have determined for it phases}, for there is no meaning in determining the moon itself into phases. The meaning is: We have determined its path into phases, which are twenty-eight. The moon descends into one of them each night, neither overstepping it nor falling short, according to a steady measure that does not vary. It travels through them each night from the new moon until the twenty-eighth, then it hides for one or two nights if the month is incomplete.

These phases are the positions of the stars to which the Arabs attributed the Anwa' (rain-bringing stars). They are: al-Sharatan, al-Butayn, al-Thurayya, al-Dabaran, al-Haq‘ah, al-Han‘ah, al-Dhirā‘, al-Nathrah, al-Tarf, al-Jabha, al-Zubra, al-Sarfa, al-‘Awwa’, al-Simak, al-Ghafr, al-Zubani, al-Iklil, al-Qalb, al-Shawla, al-Na‘a’im, al-Balda, Sa‘d al-Dhabih, Sa‘d Bula‘, Sa‘d al-Su‘ud, Sa‘d al-Akhbiya, Fargh al-Dalw al-Muqaddam, Fargh al-Dalw al-Mu’akhkhar, and al-Risha’.

When it is in its final phase, it becomes thin and curved, and {returns like the old date stalk}, which is the stem of the fruit cluster, between its branches and its base on the palm tree. Al-Zajjaj said: It is from al-in‘iraj, which is bending. It is also recited as al-‘urjun (with a different vocalization); they are two dialects. "Old" means changed by time; when it ages, it thins, bends, and yellows, so it is likened to it in three ways. It is said that the minimum duration for something to be described as "old" is a year.

{Nor does the night overtake the day}—the meaning is that God Almighty divided for each of the night and the day, and their two signs, a portion of time, set for them a known limit, and managed their affairs by succession. It is not "allowable" for the sun—meaning it is not easy, valid, or straight, because the decree is for succession—even if each of the two luminaries is given its own domain, {to reach the moon} and gather with it at one time, entering its domain and extinguishing its light. Nor does the night overtake the day; meaning the sign of the night does not overtake the sign of the day. They are the two luminaries, and the matter continues in this order until God invalidates what He has decreed and breaks what He has composed, gathering the sun and the moon, and causing the sun to rise from its setting place.

If you ask: Why is the sun described as not reaching, and the moon as not overtaking? I say: Because the sun does not complete its orbit except in a year, while the moon completes its orbit in a month. Thus, the sun is worthy of being described as "reaching" due to the slowness of its movement compared to the moon, and the moon is worthy of being described as "overtaking" due to the speed of its movement.

{And each}—the tanwin here is a substitute for the genitive addition; the meaning is "all of them," and the pronoun refers to the suns and moons as previously mentioned.