Beliefs concerning heavenly books

Allâh Ta'âla has sent down many small and large books through the angel Jibra'eel alayhis salâm to the prophets so that they may teach the matters of Deen to their respective communities. 

Among these books, four are very famous:

 the Torah which was sent to Musa alayhis salâm, the Zabur which was sent to Daud alayhis salâm, the Injil which was sent to Isa alayhis salâm, and the Quran which was sent to our Prophet Muhammad sallallahu alayhi wa sallam.

 The Quran is the last of the books.  Now, no new book will be sent from the heavens. 

The instructions of the Quran will remain valid right until the day of qiyâmah.

 Misguided people changed a lot of things in the other books. 

But Allâh Ta'âla has promised the protection of the Quran.  No one can change it in any way.

Source: Bahishti Zeevar