"[Bringing] glad tidings" of Paradise, "and a warner" against the Fire.
Muhammad [Ibn Abi Zamanin] said: "A revelation" is in the nominative case as an initial subject (mubtada'), and its predicate is "a Book." It is also permissible for it to be in the nominative case by implying 'this is a revelation.' "An Arabic Quran" is in the accusative case as a state (hal).
"But most of them turned away," that is, from it, "so they do not hear" the guidance; a hearing of acceptance.