"The Qur'ān teaches that the Jewish and Christian Scriptures were changed"
The Qur'ān says a lot of very positive things about the Jewish and Christian scriptures:
وَلْيَحْكُمْ أَهْلُ الإِنجِيلِ بِمَا أَنزَلَ اللّهُ فِيهِ وَمَن لَّمْ يَحْكُم بِمَا أَنزَلَ اللّهُ فَأُوْلَـئِكَ هُمُ الْفَاسِقُونَ
"Let the People of the Gospel judge by what Allah hath revealed therein. If any do fail to judge by (the light of) what Allah hath revealed, they are (no better than) those who rebel" (Sura Maidah 5:47)
قُلْ يَا أَهْلَ الْكِتَابِ لَسْتُمْ عَلَى شَيْءٍ حَتَّىَ تُقِيمُواْ التَّوْرَاةَ وَالإِنجِيلَ وَمَا أُنزِلَ إِلَيْكُم مِّن رَّبِّكُمْ وَلَيَزِيدَنَّ كَثِيرًا مِّنْهُم مَّا أُنزِلَ إِلَيْكَ مِن رَّبِّكَ طُغْيَانًا وَكُفْرًا فَلاَ تَأْسَ عَلَى الْقَوْمِ الْكَافِرِينَ
"Say: O People of the Book! Ye have no ground to stand upon unless ye stand fast by the Law, the Gospel, and all the revelation that has come to you from your Lord." (Sura Maidah 5:68)
فَإِن كُنتَ فِي شَكٍّ مِّمَّا أَنزَلْنَا إِلَيْكَ فَاسْأَلِ الَّذِينَ يَقْرَؤُونَ الْكِتَابَ مِن قَبْلِكَ لَقَدْ جَاءكَ الْحَقُّ مِن رَّبِّكَ فَلاَ تَكُونَنَّ مِنَ الْمُمْتَرِينَ
"If you doubt what We have revealed to you, ask those who have read the Scriptures before you." (Sura Yunus 10:94)
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 لِّلْمُتَّقِي
"And We caused Jesus, the son of Mary, to follow in their footsteps, confirming the truth of the Torah; and We vouchsafed unto him the Gospel, wherein there is guidance and light, confirming the truth of the Torah, as a guidance and admonition unto the God-conscious." (Sura Maidah 5:46)
نَزَّلَ عَلَيْكَ الْكِتَابَ بِالْحَقِّ مُصَدِّقاً لِّمَا بَيْنَ يَدَيْهِ وَأَنزَلَ التَّوْرَاةَ وَالإِنجِيلَ
"It is He Who sent down to thee (step by step), in truth, the Book, confirming what went before it (literally what is "between their hands", بَيْنَ يَدَيْهِ) ; for He has already revealed the Torah and the Gospel for the guidance of mankind, and the distinction between right and wrong." (Sura Al-'Imran 3:3)
لاَ تَبْدِيلَ لِكَلِمَاتِ اللّهِ ذَلِكَ هُوَ الْفَوْزُ الْعَظِيمُ
"None can change His Words;
that is the supreme triumph." (Sura Yunus 10:64)
