‘A’isha reported that
when the Messenger of Allah (peace be upon him) decided upon doing any act, he continued to do it, and when he slept at night or fell sick he observed twelve rak’ahs during the daytime. I am not aware of Allah’s Messenger (peace be upon him) observing prayer during the whole of the night till morning, or observing fast for a whole month continuously except that of Ramadan.
(Sahih Muslim, Book 6, Hadith 173)
