The Quran

يا أَيُّهَا الَّذينَ آمَنُوا اتَّقُوا اللَّهَ وَآمِنوا بِرَسولِهِ يُؤتِكُم كِفلَينِ مِن رَحمَتِهِ وَيَجعَل لَكُم نورًا تَمشونَ بِهِ وَيَغفِر لَكُم ۚ وَاللَّهُ غَفورٌ رَحيمٌ

Ali Unal

O you who believe! Keep from disobedience to God in reverence for Him and piety, and truly believe in His Messenger (Muhammad). He will grant you twofold of His mercy (one for your believing in all the previous Prophets, and one for the Last Prophet), and He will appoint for you a light to move (on the Straight Path in this world, leading to Paradise in the Hereafter), and He will forgive you. God is All-Forgiving, All-Compassionate.¹

Although some interpreters have thought that this verse addresses the People of the Book, it is addressed to the Muslims, though not excluding the former, in order to urge them to believe in the Last Prophet, upon him be peace and blessings. While the Jews refuse to believe in the Messengers, Jesus and Muhammad, upon them both be peace, who came after the Messengers sent to them, and the Christians refuse to believe in God’s Last Messenger, Muhammad, upon him be peace and blessings, the Muslims believe in all the Prophets. So the later deviations of the People of the Book should never cause the Muslims to have any negative opinion of any of the previous Messengers and their true followers.