Tafsir of Al-Isra 17:50

(Say) as a response to them and to bring closer that which they deemed impossible, (Be you stones or iron).

The Glorious One responded to their statement "we shall be [bones and dust]" with "be [stones or iron]" as a form of mushakala (stylistic correspondence) and responding in kind. The meaning of the imperative, as has been said, is one of disparagement, as in the words of Moses (peace be upon him): "Cast what you are going to cast." The author of al-Idah categorized it as an imperative of degradation. The learned al-Tibi considered it an imperative of subjugation, as in the words of the Almighty: "Be you apes, despised," though he noted it is based on a hypothetical premise. In al-Kashf, it is stated that this is not apparent.

If it were taken as the form "be so-and-so," in the sense of "you are so-and-so," utilizing the imperative for the purpose of an informative statement—meaning: "You are stones, not bones, and despite that, you shall be resurrected inevitably"—it would be a sound interpretation. Al-Shihab questioned this, asking how it could be said "you are stones" as a declarative statement when it does not correspond to reality. Therefore, it must be intended as degradation and indifference, making the imperative a metaphor for a declarative statement; yet this is a hypothetical declaration, and there is nothing in the text to indicate a hypothetical "if" or the conditional particles, so its remoteness from the literal sense is not hidden, and it is no closer than that which he deemed unlikely. The correct view is that it is for the purpose of disparagement, as the author of al-Idah leaned toward, so reflect upon it.

"Stones" (hijara) is the plural of "stone" (hajar), as is ahjar, and it is well-known. Likewise is "iron," which is a singular noun, with its plurals being hada'id and hadidat. It is apparent that the intent is for them to be of these two species.