And from him, from Muhammad ibn Ziyad, from Hammad ibn Uthman, from Udim ibn al-Hurr, who said: I heard Abu Abdillah عليه السلام say: "A man should not perform supererogatory (‘nafilah’) prayer once the time of an obligatory (‘faridah’) prayer has entered." And Imam عليه السلام said: "When the time of an obligatory prayer enters, begin with it."