What is the interpretation of the verse: "And We have sent down to you the Book in truth, confirming that which preceded it of the Scripture and as a guardian over it"?

The Holy Quran was revealed by Allah with truth, encompassing truth in its tidings, commands, and prohibitions. It verifies the heavenly books that preceded it and stands as a guardian over them; meaning, it contains what is in them and more. Whatever in them conforms to it is accepted, and whatever contradicts it is rejected. Allah has made for every nation a law and a methodology that varies with the changing times, to test nations with the laws He has given them. Indeed, everyone returns to Allah, and He will inform them of what they differed about. Thus, the Quran is of a higher rank than the previous books; it is a witness to their truthfulness and to the falsehood of what was corrupted in them, and a ruler concerning what Allah affirmed and abrogated, a witness in tidings and a ruler in commands.