How does a Muslim answer the question: "Will those who do not believe that there is no god but Allah and that Muhammad is the Messenger of Allah enter Hellfire or Paradise, such as Christians, polytheists, and atheists?"

Everyone who has received the call of Islam and to whom the Prophet, peace and blessings be upon him, has been mentioned, it is obligatory for them to believe in him. Whoever disbelieves after the call has reached them and the proof has been established is a disbeliever who will abide eternally in Hellfire. As for those whom the call has not reached, their ruling is the same as that of the people of the fatrah (people of the interval between prophets), and the correct view is that they will be tested in the Hereafter. Everyone who does not believe in the prophethood of Muhammad, peace and blessings be upon him, and the Qur'an after the proof has been established, is a disbeliever who will abide eternally in Hellfire. Whoever validates the religion of disbelievers or believes in their salvation has apostatized from the faith, for Allah, the Almighty, says: "And whoever desires a religion other than Islam, it will never be accepted from him, and in the Hereafter he will be among the losers" (Aal 'Imran: 85).