The Reward of Allah
Anas (radi Allahu anhu) reported that the Messenger of Allah (sal Allahu alaihi wa sallam) said, “When a non-muslim accomplishes any good deed, he is rewarded for it in this world; and in the case of a Muslim, Allah stores up his good acts for him in the Hereafter and provides him with subsistence in this life due to his obedience.”
Another narration is: The Messenger of Allah (sal Allahu alaihi wa sallam) said, “Allah does not wrong a believer a good deed because he is given blessings for it in this world and will be rewarded for it in the Hereafter. But the non-muslim is given in the world the reward for good deeds, he has performed for the sake of Allah and when he comes to the Hereafter, there is no good deed for which he can be rewarded.”
The non-muslims also do in this world many works which are for public welfare, or which come under the category of good deeds. Almighty Allah gives them reward for such good deeds in this world in the form of wealth, sound health, or saving them from some trouble, because Belief is precondition for reward in the Hereafter. Since a non-muslim is deprived of it, he will also be deprived of their reward in the Hereafter. Thus, we learn that Belief constitutes the basis of every action and is a precondition for the acceptance of any good deed by Allah.
And Allah Knows Best!