replaces the definite article al-, in the sense that the two cannot occur together. Likewise, the genitive complement replaces nunation, and nunation replaces the possessive construction, in the sense that they alternate and occupy the same position. When grammarians say that one thing replaces another, they do not mean that the replacement has the same meaning as what it replaces. Rather, each may convey a meaning that the other does not.
Thus, the Kufans meant that the definite article in “the gates” dispenses with the pronoun; alternatively, one could say “its gates.” This is correct. The purpose is to link the adjective to the noun it qualifies through something that makes it dependent on that noun rather than independent of it. Since the pronoun refers back to the qualified noun, it removes any impression of independence. The definite article does the same, for both the pronoun and the article identify what they relate to: the former identifies its antecedent, and the latter identifies the noun to which it is attached. Grammarians have likewise said that, in “Zayd—what an excellent man!”, the definite article dispenses with the pronoun. And Allah knows best.
Al-Zamakhsharī offered a grammatical analysis of this verse that has been challenged. He said: “‘Gardens of perpetual residence’ is definite, as indicated by His saying:
‘Gardens of perpetual residence which the Most Merciful has promised His servants in the unseen.’ [19:61]
It is accusative because it stands in explanatory apposition to ‘an excellent final abode.’ ‘Opened’ is a circumstantial qualifier, governed by the verbal meaning implicit in ‘the God-fearing.’ ‘Opened’ contains a pronoun referring to the gardens, and ‘the gates’ is an appositive substitute for that pronoun. The implied wording is ‘they—the gates—are opened,’ as in the expression ‘Zayd was struck—the hand and the foot.’ This is apposition of inclusion.” Such is his analysis.
The objection raised against him is that nothing in “Gardens of perpetual residence” requires it to be definite. As for His words, “which the Most Merciful has promised His servants,” these constitute an appositive substitute, not an adjective. Moreover, on his analysis, treating “Gardens of perpetual residence” as explanatory apposition to “an excellent final abode” is difficult to sustain, because no one maintains that a definite expression can follow an indefinite one in explanatory apposition. There are only two positions on this matter. The first, that of the Basran grammarians, is that explanatory apposition occurs only with definite expressions. The second, that of the Kufan grammarians and Abū ‘Alī al-Fārisī, is that it occurs with both definite and indefinite expressions, provided that the two agree in definiteness.
As for his statement that “opened” contains a pronoun referring to the gardens, the apparent construction indicates otherwise: “the gates” is made nominative by “opened,” which contains no pronoun.