Hadith 830
Sayyiduna Abu Umamah Bahili (may Allah be pleased with him) narrates: Once the Prophet Muhammad (peace and blessings be upon him) passed by him while he was moving his lips. The Prophet (peace and blessings be upon him) asked: O Abu Umamah, what are you reciting? He replied: I am remembering my Lord. The Prophet (peace and blessings be upon him) said: Shall I not tell you something which, if you recite it during the day, will be better for you than remembering (Allah) all night, and if you recite it during the night, will be better for you than remembering (Allah) all day? (The narrator is unsure, perhaps these are the words:) Recite this: “I declare the purity of Allah as many times as the number of His creation. I declare the purity of Allah as much as would fill His creation. I declare the purity of Allah as much as would fill the space between the heavens and the earth. I declare the purity of Allah as many times as is encompassed by His Book. And I declare the purity of Allah as many times as the number of everything. And I declare the purity of Allah as much as would fill everything.” (The Prophet, peace and blessings be upon him, said:) Recite “Alhamdulillah” (All praise is due to Allah) in the same manner.