What is the rhetorical subtlety in the shift from the dual to the plural address in His, the Almighty's, saying: "And We delivered them both," and "And We helped them," then its return to the dual: "And We gave them both," "And We guided them both," "And We left for them both," and "Indeed, they both were among Our believing servants"?

The expression "and We granted them victory" (ونصرناهم) in the plural form refers to Moses, Aaron, and their people. As for the dual pronouns in the rest of the verses, they refer only to Moses and Aaron, because there are two of them. Al-Razi mentioned that their victory was achieved through the manifestation of proof, and then through dominion and exaltation. Abu Al-Saud added that their victory was over their enemy after they had been subjugated.