The Revealed Books:

The Scrolls of Abraham:

Allah says:

]إِنَّ هَذَا لَفِي الصُّحُفِ الأُولَى. صُحُفِ إِبْرَاهِيمَ وَمُوسَى[
(الأعلى: 18 - 19)

This means: “Surely this is in the earliest scrolls. The scrolls of Ibrahim (Abraham) and Musa (Moses).” (87, Al-A`la: 18 - 19)

Allah says:

]أَمْ لَمْ يُنَبَّأْ بِمَا فِي صُحُفِ مُوسَى. وَإِبْرَاهِيمَ الَّذِي وَفَّى[
(النجم: 36 - 37)

This means: “Or is he not informed with what is in the Scrolls of Musa (Moses), And of Ibrahim (Abraham) who fulfilled (or conveyed) all that (what Allah ordered him to do or convey)” (53, An-Najm: 36 - 37)

The Torah:

Allah says:

]وَكَيْفَ يُحَكِّمُونَكَ وَعِندَهُمُ التَّوْرَاةُ فِيهَا حُكْمُ اللّهِ ثُمَّ يَتَوَلَّوْنَ مِن بَعْدِ ذَلِك وَمَا أُوْلَـئِكَ بِالْمُؤْمِنِينَ. إِنَّا أَنزَلْنَا التَّوْرَاةَ فِيهَا هُدًى وَنُورٌ يَحْكُمُ بِهَا النَّبِيُّونَ الَّذِينَ أَسْلَمُواْ لِلَّذِين هَادُواْ وَالرَّبَّانِيُّونَ وَالأَحْبَارُ بِمَا اسْتُحْفِظُواْ مِن كِتَابِ اللّهِ وَكَانُواْ عَلَيْهِ شُهَدَاء[
(المائدة: 43 – 44)

This means: “But how do they come to you for decision while they have the Tawrah (Torah), in which is the (plain) Decision of Allah; yet even after that, they turn away. For they are not (really) believers. Verily, We did send down the Tawrah (Torah) [to Musa (Moses)], therein was guidance and light, by which the Prophets, who submitted themselves to Allah's Will, judged the Jews. And the rabbis and the priests [too judged the Jews by the Tawrah (Torah) after those Prophets] for to them was entrusted the protection of Allah's Book, and they were witnesses thereto.” (5, Al-Ma’idah: 43 - 44)

The Injeel:

Allah says:

]وَقَفَّيْنَا عَلَى آثَارِهِم بِعَيسَى ابْنِ مَرْيَمَ مُصَدِّقًا لِّمَا بَيْنَ يَدَيْهِ مِنَ التَّوْرَاةِ وَآتَيْنَاهُ الإِنجِيلَ فِيهِ هُدًى وَنُورٌ وَمُصَدِّقًا لِّمَا بَيْنَ يَدَيْهِ مِنَ التَّوْرَاةِ وَهُدًى وَمَوْعِظَةً لِّلْمُتَّقِينَ[ (المائدة: 46)

This means: “And in their footsteps, We sent 'Isa (Jesus), son of Maryam (Mary) , confirming the Tawrah (Torah) that had come before him, and We gave him the Injeel (Gospel), in which was guidance and light and confirmation of the Tawrah (Torah) that had come before it, a guidance and an admonition for Al-Muttaqun (the pious).” (5, Al-Ma’idah: 46)

The Psalms of David

Allah says:

]وَآتَيْنَا دَاوُودَ زَبُورًا[
(الإسراء: 55)

This means: “And to Dawud (David) We gave the Zabur (Psalms).” (17, Al-Isra’: 55)

Changing the previous Revealed Books:

Allah says:

]أَفَتَطْمَعُونَ أَن يُؤْمِنُواْ لَكُمْ وَقَدْ كَانَ فَرِيقٌ مِّنْهُمْ يَسْمَعُونَ كَلاَمَ اللّهِ ثُمَّ يُحَرِّفُونَهُ مِن بَعْدِ مَا عَقَلُوه وَهُمْ يَعْلَمُونَ[
(البقرة: 75)

This means: “Do you (faithful believers) covet that they will believe our religion in spite of the fact that a party of them (Jewish rabbis) used to hear the Word of Allah (the Tawrah (Torah)) then they used to change it knowingly after they understood it?” (2, Al-Baqarah: 75)

Allah says:

]فَوَيْلٌ لِّلَّذِينَ يَكْتُبُونَ الْكِتَابَ بِأَيْدِيهِمْ ثُمَّ يَقُولُونَ هَـذَا مِنْ عِندِ اللّهِ لِيَشْتَرُواْ بِهِ ثَمَناً قَلِيلاً فَوَيْلٌ لَّهُم مِّمَّا كَتَبَتْ أَيْدِيهِمْ وَوَيْلٌ لَّهُمْ مِّمَّا يَكْسِبُون[ (البقرة: 79)

This means: “Then woe to those who write the Book with their own hands and then say, "This is from Allah," to purchase with it a little price! Woe to them for what their hands have written and woe to them for that they earn thereby.” (2, Al-Baqarah: 79)

Allah says:

]وَإِنَّ مِنْهُمْ لَفَرِيقًا يَلْوُونَ أَلْسِنَتَهُم بِالْكِتَابِ لِتَحْسَبُوهُ مِنَ الْكِتَابِ وَمَا هُوَ مِنَ الْكِتَابِ وَيَقُولُونَ هُوَ مِنْ عِندِ اللّهِ وَمَا هُوَ مِنْ عِندِ اللّهِ وَيَقُولُونَ عَلَى اللّهِ الْكَذِب وَهُمْ يَعْلَمُون[ (آل عمران: 78)

This means: “And verily, among them is a party who distort the Book with their tongues (as they read), so that you may think it is from the Book, but it is not from the Book, and they say: "This is from Allah," but it is not from Allah; and they speak a lie against Allah while they know it.”
(3, Al-`Imran: 78)

The Holy Qur’an is miraculous and safeguarded:

See the proofs in Lessons 4-7.