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

And from him, from al-Hasan, from Fadalah, from Aban, from Isma‘il al-Ju‘fi, who said: Abu Ja‘far عليه السلام said: "The best way to make up the recommended prayers (‘nawafil’) is to perform the night prayer during the night and the day prayer during the day." I said: “Will there be two ‘witr’ prayers in one night?” Imam عليه السلام said: "No." I said: “Then why do you command me to perform two ‘witr’ prayers in one night?” Imam عليه السلام said: "One of them is a make-up."