"And you were not expecting that the Book would be cast to you"—meaning the Prophet, peace be upon him. "That it would be cast to you the Book"—meaning: that it would be revealed to you. [And His saying: "expecting," He says it to the Prophet, peace be upon him] "except by a mercy from your Lord." He says: [But] He revealed the Book to you as a mercy from your Lord. "So do not ever be a supporter"—an assistant— "of the disbelievers."