Tafsir of Al-Hijr 15:31

(Except Iblis) — This is a connected exception, either because he was a single individual amidst thousands of angels, and was thus counted among them by way of generalization (taghlib), or because there is a genus among the angels that reproduces, called Jinn, and he was of them, or because he was an angel, not a jinn—and the saying of the Exalted, "He was of the jinn," is subject to interpretation, as you will come to know, God willing. His saying, the Glorified, (Refused to be with those who prostrated) is an explanatory resumption clarifying the manner of his non-prostration, which is understood from the exception—based on the principle that from affirmation comes negation, and from negation comes affirmation. This is what the soul inclines toward, for the absolute absence of prostration might occur out of hesitation, and through this, it is known that it was accompanied by refusal and arrogance.

It has also been suggested that the exception is disconnected (munqati'), in which case the sentence "refused..." is connected to what preceded it. The justification for this is that "except" (illa) carries the meaning of "but" (lakin), where Iblis is its subject and the sentence is its predicate. Thus it has been said.

In al-Ham‘, it is noted that the Basrans interpret the disconnected [exception] with lakin (heavy with tashdid). They say it is interpreted as such because it is, by nature, a sentence separate from the first. For example, your saying: "There is no one in the house except a donkey" is effectively "but there is a donkey in it." It is a rectification (istidrak) where what follows lakin contradicts what precedes it. However, they expanded the usage, treating illa as lakin. Yet, because illa is followed only by a singular noun—unlike lakin, which is followed by a complete clause—they labeled it an "exception" by analogy to it when it is an exception in reality, and to distinguish it from lakin. The Kufans interpret it as "other than" (siwa).

Some of them, including Ibn Yasa‘un, said that illa, along with the noun following it in a disconnected exception, constitutes an independent, newly initiated sentence. Regarding the verse, "And there is no one in the rub’ [abode] except the awari [tent pegs]," he said that illa is in the sense of lakin, awari is its noun in the accusative case governed by it, and the predicate is omitted, as if he said, "But the pegs are in the rub’." The predicate of illa is omitted just as the predicate of lakin is omitted in the saying, "...but a Zanj man, with large lips."

The apparent implication is that the Basrans, even though they interpret it as lakin, do not assign it this grammatical parsing; it is an interpretation of meaning, not of syntax. Perhaps the aforementioned interpretation is based on the school of Ibn Yasa‘un, though he did not explicitly state the occurrence of the predicate being expressed. Indeed, some have affirmed this, and a completion of this topic will come, God willing, in this surah, so understand.

The aspect of disconnection is clear, for it is well-known that he is not of the genus of the angels—peace be upon them—and disconnection, according to more than one, is realized by his not entering into the category of that from which the exception is made, or [not being] under its ruling. Regarding what has been said, that in such a case he would not have been commanded to prostrate, and thus [refusal] would not be binding: the excuse for this is that the Jinn were also commanded [to prostrate], and the mention of the angels—peace be upon them—rendered mentioning them unnecessary; this is the meaning of disconnection and the direction of blame [directed at him], for the narrowness of the critique [is removed].