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 Muhammad ibn Ziyad, from Kurdaywayh al-Hamdani, who said: I asked Abu al-Hasan عليه السلام, peace be upon him, about making up the ‘witr’ prayer. Imam عليه السلام said: "Whatever is after the sun’s zenith (‘zawal’) is to be prayed as ‘shaf’, two rak’ahs by two rak’ahs."