(212) Chapter: Excellence of Standing in Prayer at Night

Anas (May Allah be pleased with him) reported:
The Messenger of Allah (ﷺ) used to leave off observing Saum (fasting) during a month until we thought that he would not observe Saum at all during it; and (sometimes) he would observe Saum till we began to think that he would not omit any day of that month. If one wished to see him performing Salat during the night, he could do that; and if one wished to see him sleeping at night, he could do that.

[Al- Bukhari].

Commentary: What this Hadith tells us is that whether it was optional Saum (fasting) or optional Salat (Nawafil) of the night, that is to say Qiyam-ul-Lail, the Prophet (PBUH) did not have a permanent routine for it. Sometimes it so happened that almost the month passed but he did not observe fasting and then a few days before the end of the month he would start fasting. Sometimes, he would fast day after day continuously, and it would appear as if he would continue fasts for the whole month, but he would then suddenly terminate fasts. Similar was the case of Tahajjud. Sometimes, he would perform Tahajjud prayer in the first portion of the night, sometimes in the second, and sometimes in its later portion. Thus, he was found sleeping and performing Salat in every part of the night.