Sahih Muslim Book 001, Hadith Number 0416.
Chapter : Proof in support of the fact that he who died in unbelief, his deed would not be of any avail to him.
'Aisha reported: I said: Messenger of Allah, the son of Jud'an established ties of relationship, fed the poor. Would that be of any avail to him? He said: It would be of no avail to him as he did not ever say: O my Lord, pardon my sins on the Day of Resurrection.