Sayyiduna Abu Umamah (may Allah be pleased with him) narrates: I said, "O Messenger of Allah (peace and blessings be upon him)! Guide me towards a deed." The Prophet (peace and blessings be upon him) said, "You must observe fasting, for there is nothing equal to it." (Imam Ibn Hibban, may Allah have mercy on him, says:): This narrator named Abu Nasr is Humaid bin Hilal. I do not deny the possibility that Muhammad bin Abu Ya'qub heard this narration in detail from Raja', and then he heard a part of it from Humaid bin Hilal, so both of its chains will be preserved.