Tafsir of Ar-Rahman 55:6

For the conjunctive particle (the wa in wa-al-najm) connects to a predicate, and the predicate is a predicate. The intent behind "the star" (al-najm) is the vegetation that emerges—that is, it appears and rises from the earth—having no trunk, and "the trees" (al-shajar) is the vegetation that has a trunk. This is what has been narrated from Ibn Abbas, Ibn Jubayr, and Abu Razin.

The intent behind their prostration is their submissiveness to Him, the Almighty, in what He wills for them by nature. Their course according to the requirements of their nature is likened to the submission of a prostrator to his Creator and his glorification of Him; then, the name of the object of comparison was used for the subject of comparison, so it is an explicit metaphorical substitution (isti‘arah musarrahah taba‘iyyah).

Mujahid, Qatadah, and al-Hasan said: "The star" is the star of the sky, and its prostration is its setting and the like, while the prostration of the trees is through their shadows, and their turning, according to Mujahid and al-Hasan. In another narration from Mujahid, he says that their prostration is an expression of their submission to what He, the Glorified, wills for them by nature. The majority prefer the first interpretation of "the star" mentioned, because its pairing with "the trees" indicates it. Even if the preceding mention of "The sun and the moon" suggests it has its well-known meaning, there is a clear tawriyah (double entendre) in it.

The second, third, and fourth sentences are devoid of conjunctions because they are brought in the manner of enumeration, while indicating that each of the things mentioned is independent, requiring gratitude that was fallen short of in its performance. If they had been conjoined despite their intense connection and proportion, it might have been imagined that they were all a single blessing.

The placement of the conjunction between the fourth and fifth [sentences] is in observance of their correlation in terms of contrast, as "the sun and the moon" are heavenly, while "the star and the trees" are earthly, and because the state of the two heavenly bodies and the state of the two earthly ones both belong to the category of submission to the command of Allah, the Exalted. They are devoid of a linguistic connective, despite both being predicates, in reliance upon the complete strength of the semantic connection, for the mind would not imagine that the state of the sun and the moon is via the subjugation of other than Him, the Exalted, nor that the prostration of the star and the trees is for other than Him, the Glorified. It is as if it were said: "The sun and the moon are by calculation, and the star and the trees prostrate" to Him. This is how they stated it.

In al-Kashshaf, as a clarification of what the author mentioned in this place: he left the sentences—that is, those before "The sun and the moon are by calculation"—without a conjunction, because the purpose is the enumeration of blessings and the rebuking of the denier. Just as one says: "He enriched you after poverty, He honored you after abasement, He increased you after scarcity; He did for you what no one has done for anyone—so what is it of His beneficence that you deny?" It is as if, when he counts a blessing, he stirs the person so that he reflects on whether he has given it its due gratitude or not, then he begins with another. If the conjunction were used, they would become as one, and there would be no stirring at all. When he fulfilled the need for the stirring enumeration and the rebuke, he followed it by mentioning the origin of blessings in a manner that returns the speech to its original path of enumerating blessings one after another, according to their proportion and proximity, using the particle of sequence. In this is an alert that blessings are uncountable, so it is sufficient to enumerate the highest of them in rank for the mentioned purpose.

The sentence "The sun and the moon are by calculation" is not among the predicates of the subject. Al-Zamakhshari only asked about the aspect of connection and replied that the connection is achieved through semantic linkage. It is as if, after he rebuked and alerted, he began to enumerate the foundations of blessings for him so that he would be rewarded for the gratitude demanded of him. This is as you say in the previous example after saying: "He did for you what no one has done for anyone; your peers submitted to him, your brothers obeyed him, he spread his bounty among those under his dominion, and no one escaped the perimeter of his justice and fairness." No person of intellect doubts that these are sentences grammatically disconnected from the first, yet connected to it semantically—a connection caused by their disconnection, for this was brought for a purpose and that for another. Close to this connection is the connection of His saying: "Indeed, those who disbelieve—it is all the same for them..." with His saying: "Those who believe in the unseen..." (the verse).

The meaning is far-fetched, in my view, unless the literal words of al-Kashshaf require that His saying "The sun and the moon are by calculation" be among the predicates. So reflect.