Tafsir of Al-A'raf 7:115

They said: This is a resumption, similar to its predecessor: "O Musa, either you cast," meaning "what you are casting first," or "we will be the ones casting first." They gave him, peace be upon him, the choice to begin the casting out of observance of etiquette, as has been said, or to display boldness and show that it makes no difference to them whether the action is prioritized or delayed. However, their desire was to go first, as indicated by their alteration of the structure through the definition of the predicate, the insertion of the separator pronoun, and the emphasis of the hidden pronoun. It is apparent that what was narrated occurred in this manner using synonymous terms.

As for the statement of Jalal al-Suyuti—that the detached pronoun is either a separator or an emphasis, and it is impossible to combine both because, in the first case, it has no place in syntax, whereas in the second, it has a place like the word being emphasized—this is clear. Al-Tibi distinguished between the pronoun being a separator and its being an emphasis: that emphasis removes figurative interpretation from the subject, thus necessitating specification through the definition of the predicate—meaning "we are the ones who cast, absolutely, and no one else"—whereas the separator specifies the action of casting to them by confining the predicate to the subject, thereby remaining devoid of emphasis. The verification of this is sought in its proper place.