According to the doctrine of many Muslims today, the Scriptures that preceded the Qur’an were changed and replaced by the Qur’an. The Qur’an, however, only says that the meaning of the words has been distorted (IV 46; V 13; V 41), or was twisted with the tongues (cf. III 78). This does not mean that the words themselves have been distorted.
Jews, Christians and Muslims may know this problem from conversations between the different camps within their own religion. For example, between liberal and orthodox Jews or between protestant and catholic Christians or between shiite and sunni Muslims. Everyone is convinced, the other understands something wrong, he distorts the meaning of Scripture.

On the contrary, the Qur’an itself, which I think is crucial, assures us: “We revealed the Reminder, and We verily are its Guardian.” (XV 9)  With this verse Muslims justify why the Qur’an is the unadulterated word of GOD. However,  the preservation which is guaranteed by GOD, is not the Qur’an, but the “Reminder“.

The Qur’an does not only describe itself as a Reminder and guidance, but also the Tora and the Gospel.
“And We verily gave Moses and Aaron the Criterion (of right and wrong) and a light and a Reminder for those who keep from evil, Those who fear their Lord in secret and who dread the Hour (of doom). This is a blessed Reminder that we have revealed: Will you then reject it ?” (XXI 48-50)

“And in their footsteps We made Jesus, the son of Mary, follow, to confirm the Tora that was before him. And We gave him the Gospel with guidance and light, confirming the Tora that was before it, as a guidance and a Reminder for the God-fearing.” (V 46)

Moreover, Jews and Christians are called in the Qur’an ‘followers of the Reminder‘: “And We sent not (as Our messengers) before thee other than men, whom We inspired. Ask the followers of the Reminder if you know not?” (XXI 7)

“He has revealed unto you (Muhammad) the Scripture with truth, confirming that which was (revealed) before it, even as He revealed the Tora and the Gospel. Aforetime, for a guidance to mankind; and has revealed the Criterion (of right and wrong)…” (III 3-4)

The Qur’an goes on to say: “And recite that which has been revealed unto you of the Scripture of your Lord. There is none who can change His words, and you will find no refuge beside Him.” (XVIII 27)

At this point I see another important confirmation not only of the Qur’an, but also of the Tora and the Gospel, as the unadulterated word of GOD. For “the Scripture” whose word no one changes, the Qur’an refers not only to itself, but also to the Tora and the Gospel.

“Who has sent down the Scripture which Moses brought as a light and a guide for mankind, and which you treat as mere paper [. . . ]” (VI 91)

“And He will teach him (Jesus) the Scripture and wisdom, and the Tora and the Gospel…” (III 48)

The Qur’an says: “And the Jews say ‘the Christians are not based on anything’ and the Christians say ‘the Jews are not based on anything’; Yet they read the Scripture. With similar words spoke (already) those who did not at all possess knowledge”. ( II 113)

This verse wants to make it clear that both Scriptures, the Tora and the Gospel, should be read as the Word of GOD.

“Yet they read the Scripture” seems particularly important to me. Thus it becomes clear that the Tora and the Gospel are not, as often said by Islamic scholars, any other or today no longer findable Scriptures, but rather those which Jews and Christians read. With regard to the Tora, these are the five books of Moses, and with regard to the Gospel, the Gospels according to Matthew, Mark, Luke, and John.

“Those unto whom We have given the Scripture, who read it with the right reading, those believe in it.”   (II 121)

“Say O People of the Scripture! You have no guidance untill you observe the Tora and the Gospel and that which was revealed unto you from your Lord.”(V 68)

And maybe once again, because it may show you how precious this knowledge is, because it gives you all the blessings you can get in this world and the hereafter:  “If they followed the Tora and the Gospel, and what was sent down to them from their LORD, then truly they would be fed on what is above them and at their feet.”  (Sure V, verse 66).

In addition, I would like to point out that in the Gospel Jesus also includes the Tora and the preceding prophets as a binding basis.

Jesus says:
“Think not that I came to abolish the law and the prophets. I did not come to abolish, but to fulfill. Amen, I say to you, until heaven and earth pass away, not even the smallest letter of the law shall pass away, until all things are done. Whoever abolishes even one of the smallest commandments, and teaches men according to it, will be the smallest in the Kingdom of Heaven. But whoever keeps and teaches them will be great in the Kingdom of Heaven. Therefore I say to you, unless your righteousness is far greater than that of the scribes and Pharisees, you will not enter the Kingdom of Heaven”. (Mt 5:17-20)