Narrated `Aisha: Allah's Apostle used to fast till one would say that he would never stop fasting, and he would abandon fasting till one would say that he would never fast. I never saw Allah's Apostle fasting for a whole month except the month of Ramadan, and did not see him fasting in any month more than in the month of Sha'ban.

Narrated Anas bin Malik: Sometimes Allah's Apostle would not fast (for so many days) that we thought that he would not fast that month and he sometimes used to fast (for so many days) that we thought he would not leave fasting throughout that month and (as regards his prayer and sleep at night), if you wanted to see him praying at night, you could see him praying and if you wanted to see him sleeping, you could see him sleeping.

Narrated `Aisha: The Prophet never fasted in any month more than in the month of Sha'ban. He used to say, "Do those deeds which you can do easily, as Allah will not get tired (of giving rewards) till you get bored and tired (of performing religious deeds)." The most beloved prayer to the Prophet was the one that was done regularly (throughout the life) even if it were little. And whenever the Prophet offered a prayer he used to offer it regularly .

Narrated Anas: Allah's Apostle used to leave fasting in a certain month till we thought that he would not fast in that month, and he used to fast in another month till we thought he would not stop fasting at all in that month. And if one wanted to see him praying at night, one could see him (in that condition), and if one wanted to see him sleeping at night, one could see him (in that condition) too.

Narrated `Aisha: The Prophet was asked, "What deeds are loved most by Allah?" He said, "The most regular constant deeds even though they may be few." He added, 'Don't take upon yourselves, except the deeds which are within your ability."