Sayyiduna Abdullah bin Amr bin al-As (may Allah be pleased with him) narrates: The Prophet Muhammad (peace and blessings be upon him) came to know that I had said: As long as I live, I will continue to offer voluntary prayers throughout the night and fast during the day. The Prophet Muhammad (peace and blessings be upon him) said: Did you say this? I replied: O Messenger of Allah! I did say this. The Prophet Muhammad (peace and blessings be upon him) said: You will not be able to do this. Fast some days and leave it some days (at night) sleep as well and also offer voluntary prayers. Fast three days in every month; the reward of a good deed is tenfold, so it will be as if you have fasted all the time. I said: I have the strength to do more than this. The Prophet Muhammad (peace and blessings be upon him) said: Fast one day and do not fast the next day. This is the way of fasting of Sayyiduna Dawood (peace be upon him) and this is the most appropriate way of fasting. I said: I have the strength to do more than this. The Prophet Muhammad (peace and blessings be upon him) said: There is no allowance for more than this. Sayyiduna Abdullah (may Allah be pleased with him) says: If I had accepted what the Prophet Muhammad (peace and blessings be upon him) had said about fasting three days, it would have been more beloved to me than my family and wealth.

(Imam Ibn Hibban, may Allah have mercy on him, says:) The statement of the Prophet Muhammad (peace and blessings be upon him): "There is no greater virtue than this in anything." By this, the Prophet Muhammad (peace and blessings be upon him) meant: For you, there is not. The reason is: The Prophet Muhammad (peace and blessings be upon him) knew about Sayyiduna Abdullah bin Amr (may Allah be pleased with him) that he would become weak regarding the good deeds he was obligating upon himself.