Does a Muslim become an unbeliever if he is not convinced of the unbelief of an unbeliever, even if he prays and believes in the Quran and Sunnah? And can he consider Jews and Christians believers who will enter Paradise after the truth has been clarified to them, and yet remain a Muslim?

Whoever does not believe in the disbelief of a disbeliever whose disbelief is unanimously agreed upon, has not believed what Allah Almighty has informed us about their disbelief, nor has he believed that Islam abrogates the religions that preceded it, and that everyone must follow this religion. Allah Almighty says: (And whoever seeks a religion other than Islam, it will never be accepted of him, and in the Hereafter he will be among the losers), and He says: (Say, "O mankind, indeed I am the Messenger of Allah to you all").

Qadi Iyad transmitted the excommunication of anyone who adopted a religion other than that of the Muslims, or doubted them, or affirmed the validity of their doctrine, even if they outwardly professed Islam.

Shaykh Muhammad ibn Abd al-Wahhab mentioned that among the greatest nullifiers of Islam are: polytheism, and whoever places intermediaries between himself and Allah, calling upon them, and whoever does not declare polytheists as disbelievers, or doubts their disbelief, or affirms the validity of their doctrine. These nullifiers apply to the jester, the serious, and the fearful, except for one who is coerced.

Disbelief and polytheism are the same in ruling according to Ibn Hazm, Al-Shafi'i, and others. Jews and Christians are disbelieving polytheists, based on Allah Almighty's saying about the Jews: (And the Jews say, "Ezra is the son of Allah") and about the Christians: (And the Christians say, "The Messiah is the son of Allah") and His saying: (They have certainly disbelieved who say that Allah is Christ, the son of Mary), (They have certainly disbelieved who say that Allah is the third of three).

And whoever says that Jews or Christians are not disbelievers, he is denying many verses from the Holy Quran, and the Hadith of the Prophet, peace and blessings be upon him: "By the One in Whose hand is the soul of Muhammad, no one from this nation, neither a Jew nor a Christian, hears of me, and then dies without believing in that with which I was sent, except that he will be among the people of the Fire."