The View of Shaykh al-Islam Ibn Taymiyyah (d. 728 A.H.)
With regard to the Gospels that the Christians have, there are four Gospels, Matthew, Mark, Luke and John. They are agreed that Luke and Mark did not see the Messiah; rather he was seen by Matthew and John. These four accounts that they call the Gospel, and they call each one of them a Gospel, were written by these men after the Messiah had been taken up into heaven. They did not say that they are the word of God or that the Messiah conveyed them from God, rather they narrated some of the words of the Messiah and some of his deeds and miracles. (Ibn Taymiyyah, al-Jawaab al-Saheeh, (3:21), cited here)
The View of Ibn Kathir, the student/disciple of Ibn Taimiyyah, says:
Our Sheikh the notable Imam Abul-‘Abbas Ibn Taimiyyah said: As for those who argued that it [the Torah] is entirely corrupted from beginning to end without sparing one letter, they are mistaken. Also, those who argued that nothing has been corrupted are mistaken. The truth is that alteration and change had reached it and they [the Jews] manipulated its words with additions and omissions as they manipulated its meanings. This is well recognized on pondering and may be explained in another occasion, and Allah knows best….(Ibn Kathir, Al-Bidayah wa Al-Nihayah, Volume 2, pages 152-153)
Clearly Ibn Taymiyyah does not believe that the Gospels of Matthew, Mark, Luke and John are the Gospels that were revealed by Allah. Thus believing that the original and true Gospel has been textually corrupted.
Shaykh ibn Taymiyyah’s famous book al-Jawaab al-Saheeh in refuting the Christians could be read here.
From Call to Monotheism