Sahih Adab al-Mufrad

Narrated from Sayyiduna Abbas bin Abdul Muttalib (may Allah be pleased with him) that he said: I submitted, "O Messenger of Allah! Teach me a supplication by which I may ask Allah." The Prophet (peace and blessings be upon him) said: "O Abbas! Ask Allah for well-being." Then he remained silent for three days. Then I came and said: "O Messenger of Allah! Teach me something by which I may ask Allah." So the Prophet (peace and blessings be upon him) said: "O Abbas! O uncle of the Messenger of Allah! Ask Allah for well-being in this world and the Hereafter."