Why was verse 13 of Surah Ar-Rahman: (Then which of the blessings of your Lord will you both deny?) mentioned, even though the first mention of humans and jinn came immediately after it, and not before it?

The verse refers to a dual address, and many scholars have interpreted it as an address to both jinn and humankind. However, some have interpreted it as an address to humankind only, arguing that it follows the Arab custom of addressing a single entity with a dual form.

What supports the first opinion, that the address is to both jinn and humankind, is the occurrence of the word "al-anam" (creation/beings), which encompasses both, and the explicit direction of the address to them in subsequent verses such as: "We will soon attend to you, O you two heavy ones (jinn and humankind)" and "O company of jinn and humankind."

The majority of exegetes have agreed that the address in the verse is directed to both jinn and humankind, and that the Qur'an is like a single surah (definition). If the accountability of jinn and humankind is established, then both species are addressed by the verses. Some scholars point out that Arabs may address a single entity with the dual form, but the more correct view is that the address from the beginning of the surah to its end includes both jinn and humankind.