Abu Malik al-Ashja'i narrates from his father: We used to go to the Prophet (peace and blessings be upon him) in the morning, and a man or a woman would come and say: O Messenger of Allah, what should I say when I pray? And he (peace and blessings be upon him) would say: "Say: O Allah, forgive me, have mercy on me, guide me and provide for me; for these words gather for you both your world and your Hereafter."
Hadith Referenceالمعجم الكبير للطبراني / باب الطاء / 8152