This is how to distinguish between the true religion and a false religion: 1- The true religion should have come from Allah, 2- It should call for the worship of Allah alone, 3- It should be in accordance with the principles advocated by the Messengers, 4- It should not be self-contradictory, 5- It should guarantee to protect people’s religious commitment, honour, wealth, lives and children, 6- It should be a mercy to mankind, 7- It should include guidance regarding the laws of Allah, 8- It should advocate the best attitudes and actions, 9- It should bring happiness to those who believe, and 10- It should point towards the truth and warn against falsehood.

Islam considers other religions to be either fabricated and false, or abrogated. The fabricated and false religions are those like the ancient Arabian practise of worshipping idols and stones. The abrogated religions are those which were taught by the Prophets who came before our Prophet Muhammad (peace and blessings be upon him).

Muslims believe that there is only One God and that Prophet Muhammad (peace and blessings be upon him) is His Messenger. They also believe that Jesus was a human being with no divine qualities. Christians, on the other hand, believe in the divinity of Jesus as the Son of God and the second person of the holy trinity. They hold that divinity can be incarnated in humanity and that Jesus (Peace be upon him) was crucified by the Jews, dying on the cross as a ransom for mankind to atone for original sin.

Conclusion: The Christians may have been excused for their belief in the killing and crucifixion of the Messiah, before the sending of our Prophet Muhammad (blessings and peace of Allah be upon him). But after his sending (blessings and peace of Allah be upon him) and the establishment of proof and miracles to confirm his truthfulness and Prophethood, there is no excuse for those against whom proof is established, and whom the message of Islam and the Quran have reached, for going against anything that the Messenger of Allah (blessings and peace of Allah be upon him) brought. We have not discussed this answer at length, as what we have mentioned previously in fatwas no. 224199 and 225709 is sufficient. And Allah knows best.