And this narration does not contradict the report we previously presented, which is the narration of Abu Basir from Abu Abdillah عليه السلام, peace be upon him, when he mentioned the ruling of one who forgot a prostration and did not remember it until after the bowing. Imam عليه السلام said: "He makes it up after the prayer, and there is no prostration for forgetfulness upon him." His saying, peace be upon him, ‘and there is no prostration for forgetfulness upon him,’ only means that his ruling is not the ruling of those who are forgetful (sahin), but rather the ruling of those who interrupt the act, because when he remembers what he missed and makes it up, nothing remains for him to be in doubt about, thus he exits the state of forgetfulness. As for what is contained in the narration of al-Halabi, that if one doubts whether it was one prostration or two, he should add a prostration, and there is no prostration for forgetfulness upon him, this applies to one for whom this is the ruling. And we have only made the two prostrations of forgetfulness obligatory upon one who realizes after the bowing that he left out a prostration, for such a person makes it up after the taslim and then performs the two prostrations of forgetfulness.
Commentary #21