Chapter on the Manner of Prayer, Its Description and What is Obligatory and Recommended

Ali ibn Ibrahim from his father from Abdullah ibn Al-Mughira from Ibn Muskan from Al-Hasan Al-Sayqal from Abu Abdillah عليه السلام, peace be upon him, who said: I said to Him عليه السلام: “A man prays the two rak'ahs of witr, then he stands and forgets the tashahhud until he bows, and remembers while bowing.” Imam عليه السلام said: "He should sit from his bowing, perform the tashahhud, then stand and complete (his prayer)." I asked: “Did you not say regarding the obligatory prayer that if he remembers after bowing, he should continue, then perform the two prostrations of forgetfulness after he finishes and recite the tashahhud in them?” Imam عليه السلام said: "The supererogatory prayer (nafila) is not like the obligatory prayer (faridah)."