Iman (faith) is a condition for salvation in the hereafter. Of course, Hell is the abode of such a person who leaves this world in a state that he even does not have a small particle of faith. Good deeds done without faith will have no importance in the hereafter. Non-Muslims who do good deeds in this world they are given its requital in the form of reputation, popularity, wealth etc in this very world. They have no share in hereafter. Those who deem their Hindu religion good they are in false belief. After Islam, all the other religions of the world have ceased to be accepted before Allah. Allah has favoured every one with perception and intellect by which they can observe lots of sings in the world that portray the Oneness of God. If man ponders over these signs he can recognize his real Creator and can acknowledge the Divinity and Oneness of God. There is no room to reject the Oneness of God when there are proofs and signs of it:
روى عن أبي حنيفة : لا عذر لأحد فى الجهل بخالقه لما يرى من الدلائل . (مسلم الثبوت)
Further, Islam has reached in every nook and corner of the world. Specially in today’s age that is the age of electronic communication and computer there may hardly be anyone who does not know this religion. Therefore, the viewpoint that “billions of non-Muslims who are following the religion of their forefathers and they do not know about true religion of Islam” is null and void. Their ignorance is not an excuse rather it is their fault. It is mandatory for them to know the true religion that is only Islam. They should accept it and adopt its teachings. If they do not do so then they cannot escape from accountability in the hereafter.
Allah knows Best!
Darul Uloom Deoband