Belief in the Books implies four things:
1. One should have a firm belief that all of them were revealed from Allah and that they were all spoken by Him in the real sense. Some of these books were heard from him from behind a veil without any intermediary from among the angels. Some of the words of Allah were conveyed by an angelic messenger to the human messenger. Some were written by Allah with His own hand as He says (interpretation of the meaning):
“It is not given to any human being that Allah should speak to him unless (it be) by Revelation, or from behind a veil, or (that) He sends a Messenger to reveal what He wills by His Leave. Verily, He is Most High, Most Wise.” [42:51]
“… and to Musa Allah spoke directly.” [4:164]
And Allah said concerning the Tawrat:
“And We wrote for him on the Tablets the lesson to be drawn from all things and the explanation for all things.” [7:145]
2. The Books that Allah has mentioned by name, we must believe in by name. These are the Books which Allah has named in the Quran, i.e., the Quran, the Tawrat, the Injeel (Gospel), the Zaboor (Psalms), and the Scriptures of Ibrahim and Musa.
Those which Allah has mentioned in general terms, we must believe in them in general terms, so we say concerning them what Allah and His Messenger have commanded us to say:
“…say: “I believe in whatsoever Allah has sent down of the Book [all the holy Books…].” [42:15 – interpretation of the meaning]
3. Believing in the words of these books that these are true such as what is said in Quran and whatever has not been altered in previous books.
4. Believing that Allah revealed the Quran as a witness to all other books and confirm them as true and words of Allah. Allah says (interpretation of the meaning):
“And We have sent down to you (O Muhammad) the Book (this Quran) in truth, confirming the Scripture that came before it and Muhaymin (trustworthy in highness and a witness) over it (old Scriptures).” [5:48]
Quram is a trustworthy books that is a witness over the books that came before it and confirms in them. It confirms whatever is true in them and rejects the alteration therein. Quran is a witness that the laws and rulings in these books are no longer applicable and that new rulings and laws have been promulgated. Hence all those who were following previous books and who have not turned on their heels should submit to it, as Allah says (interpretation of the meaning):
“And when it is recited to them, they say: We believe in it. Verily, it is the truth from our Lord. Indeed even before it we have been from those who submit themselves to Allah in Islam as Muslims.” [28:52-53]
It is obligatory for all the ummah (followers of Muhammad) to follow the Quran both outwardly and inwardly, and to adhere to it, and give it its due, as Allah says (interpretation of the meaning):
“And this is a blessed Book (the Quran) which We have sent down, so follow it and fear Allah.” [6:155]
What is meant by adhering to the Quran and giving it its due is: regarding what it permits as permitted, regarding what it forbids as forbidden, obeying its commands, avoiding that which it prohibits, paying heed to its lessons, learning from its stories, understanding its clear and unambiguous texts, referring the exact meaning of its ambiguous texts to Allah, not overstepping its limits and defending it, whilst memorizing it, reciting it in a proper manner, pondering the meanings of its verses, reciting it in prayer night and day, being sincere towards it in all senses, and calling others to do likewise with understanding.
This belief will bear great fruit for a person, the most important of which is:
1. Having knowledge of Allahs care for His slaves that He has revealed to each people His book by which they may be guided.
2. Having knowledge and belief in Allahs wisdom by which He has set out laws and rules for the people according their circumstances. Allah says (interpretation of the meaning): “To each among you, We have prescribed a law and a clear way.” [5:48].
3. Being greatful and fulfilling the duty of giving thanks to Allah for His blessings and Mency.
4. It is important to pay attention to Quran by reading and reciting it, pondering upon its meanings and acting accordingly..
And Allah knows best.