Surah 40. Ghafir, Ayah 70

Since, as the Qur'an so often points out, the fundamental truths set forth in all divine revelations are the same, a rejection of the last of them amounts to a rejection of all the preceding ones.

"The Book" may refer to the Holy Qur-an or to the fundamental, Revelation the "Mother of the Book" (xiii. 39), while the Books revealed to the messengers are the definite Revelations that came down to men from time to time.