"And thus We have revealed to you a spirit" (Q. 42:52), meaning: the Quran, "of Our command."
Muhammad said: The meaning of "a spirit" (ruhan) is: that by which creation is guided, for it is a life [from misguidance].
"You did not know," before We revealed it to you, "what the Book was, nor what the faith was, but We made it," meaning: the Quran, "a light," that is: an illumination from darkness, "and indeed, you guide," meaning: you call "to a path," meaning: a way, "that is straight."