Chapter on the Detailed Explanation of Prayer, Including the Obligatory and Recommended, and What is Permissible and Not Permissible.

Ali ibn Mahziyar, from al-Hasan, from Hammad ibn ‘Isa, from Hariz, from Zurarah, who said: (It was said) "If you miss your ‘witr’ from the night, then whenever you make it up the next day before the sun’s zenith, you make it up as ‘witr’. And whenever you make it up at night, you make it up as ‘witr’. But whenever you make it up during the day after that (after that day), you make it up as ‘shaf’, you add to it another rak’ah so that it becomes even." I asked: “Why is it made ‘shaf’?” Imam عليه السلام said: "As a punishment for neglecting the ‘witr’."