It is narrated from Hazrat Aisha (may Allah be pleased with her) that sometimes the Prophet (peace and blessings be upon him) would fast so much that we would say, "Now the Prophet (peace and blessings be upon him) will continue to fast," and sometimes he would leave off fasting so much that we would say, "Now the Prophet (peace and blessings be upon him) will continue to leave off fasting." And I have not seen the Prophet (peace and blessings be upon him) fast in any month as much as I saw him fast in Sha'ban; he would fast almost the entire month, leaving only a few days.