Tafsir of Ad-Dhariyat 51:17

Their benevolence is interpreted by His saying, the Exalted: "They were, but few of the night, what they would sleep," on the basis that the sentence is in the nominative case as a substitute for His saying, "They were before that doers of good," whereby this sentence serves as its interpretation, or that it is a sentence with no syntactic place, functioning as an explanatory clause like other explanatory sentences. Al-Faryabi, Ibn Jarir, Ibn al-Mundhir, and Ibn Abi Hatim narrated from Ibn Abbas—may Allah be pleased with them both—that he said regarding the verse: "Taking what their Lord gave them" of the obligatory duties; "They were before that doers of good," meaning they were, before the revelation of the obligatory duties, doing [good deeds]. I do not believe the attribution of this to that learned scholar is authentic, and if what is reported from him regarding its interpretation were correct, the sentence "They were..." would hardly be made an explanation for it. God willing, this will be discussed further.

Al-huju’ (slumber) is sleep. Al-Raghib restricted it by saying: "at night," while others restricted it to "a little."

As for ma (what):

1. It is an expletive (extra), so qalilan (few) is the object of the verb acting as an adjective for an elided verbal noun, meaning: "they slept a little sleep." Min al-layl (of the night) is an adjective or a loosely connected prepositional phrase linked to yahja’un (they sleep), with min indicating the inception of the action. The sentence yahja’un is the predicate of kana (they were).
2. Or, qalilan is an adjective for an elided temporal adverb, meaning: "for a little time," and min al-layl is an adjective, similar to the phrase "I have a little of wealth."
3. Or, it is a relative pronoun with its referent omitted, acting as the subject of qalilan, which is the predicate of kana; and min al-layl is a circumstantial qualifier (hal) for the relative pronoun, placed in front. It is as if it were said: "The amount they used to sleep had become little, and that amount existed 'from the night'."
4. Or, it is an infinitive (masdariyyah), so the resulting source/infinitive is the subject of qalilan, which is also the predicate of kana; and min al-layl is an explanatory phrase, not linked to what follows it, because the object of an infinitive cannot precede it, or it is a circumstantial qualifier for the infinitive, with min indicating inception. Such is found in al-Kashf, derived from al-Kashshaf.

Some have argued that min is used in the sense of "in," as in the Exalted's saying: "When the call is made for prayer from [i.e., on] the day of Friday." Ibn al-Munir objected to the infinitive possibility, arguing that it is not permissible for min al-layl to be an adjective or explanation for qalilan because it is located after the sleeping, nor can it be connected to the infinitive because of its precedence. It was answered that it is an explanation for the vague time. Al-Tayyibi recounted that it is either in the accusative as a clarification or linked to a verb explained by yahja’un. He also permitted that ma yahja’un could be a substitute for the noun of kana, as if it were said: "Their sleeping was little," but this is far-fetched.

He also permitted that ma could be negative, and qalilan could be in the accusative governed by yahja’un, the meaning being: "They would not sleep a little bit of the night, but would spend it all awake." Ibn Abi Shaybah and Abu Nasr narrated this from Mujahid, but al-Zamakhshari refuted it by saying that the negative ma does not allow its subsequent part to govern what precedes it, because it occupies the beginning of the sentence and does not possess the flexibility found in its sisters. This is not absolute, for it can be part of what it enters into, like [the phrase] "He was rebuked without a crime" (la jurmin); and lam and lan [are similar], as they are exclusive to the verb and function like part of it. You know that the prohibition of such governance is the school of the Basrans. In the commentary of al-Hadi, some grammarians permitted it absolutely, and some permitted it specifically for adverbs due to the flexibility afforded to them, citing as evidence the verse: "And we have not, regarding your favor, been free of need."

Yes, it is countered that this contains a flaw in terms of meaning, as mentioned in al-Intisaf, because the requirement to stand the whole night in prayer—without any exemption for sleep, however little—is not established in the Sharia, nor is it customary. Unless, of course, one claims that those who held this view say it was established in the Sharia, as Ibn Abi Shaybah and Ibn al-Mundhir narrated from Ata’ that he said regarding the verse: "That was when they were ordered to stand the whole night in prayer, so Abu Dharr would lean on a staff; they remained like that for two months, then the concession was revealed: 'So recite what is easy of it.'"

Al-Dahhak said: "They were few" refers to their number, and the sentence ends at "few," then he begins: "of the night what they would sleep," with ma being negative. This involves what was mentioned previously, with additional disjointing of the speech. Perhaps the most apparent of these viewpoints is that ma is expletive, qalilan is in the accusative as an adverb, and min al-layl is an adjective. It is said that the speech contains exaggerations: the word huju’ based on it being the small amount of sleep; the Exalted's word qalilan; and min al-layl because the night is the time for rest and tranquility; and the addition of ma because it emphasizes the content of the sentence, thereby confirming the scarcity and verifying it by virtue of its being a restriction within it.

The purpose of the verse is that they would endure the toil of worship during times of rest and stillness of the soul, and they would not rest from the hardships of the day except for a little. Al-Hasan said: "They endured standing the night; they would not sleep from it except a little." From Abdullah ibn Rawaha: "They slept a little, then they stood [for prayer]." Anas ibn Malik interpreted the verse—as a group narrated from him and al-Hakim authenticated it—saying: "They used to pray between the Maghrib and the Isha," though this does not indicate restricting it to only that.