These narrations are understood as referring to cases where the man was unaware that she was menstruating. However, if he knowingly commits the act, he is required to pay the expiation as mentioned earlier. It is not valid to claim that this interpretation is impossible because, even in cases of forgetfulness, the statements that he "should seek forgiveness from his Lord" or "has disobeyed his Lord" can still apply. This is because failing to ask her about her condition, knowing that intercourse would be forbidden if she were menstruating, constitutes negligence. By this negligence, he disobeyed and is required to seek forgiveness because he engaged in an act that he could not be certain was permissible. The correctness of this interpretation is clarified by the earlier narration of Laith Al-Muradi, where he said: "I asked Abu Abdullah عليه السلام about a man who mistakenly had intercourse with his wife while she was menstruating." The question specifically framed the act as unintentional, and Imam عليه السلام replied: "There is nothing obligatory upon him, but he has disobeyed his Lord." As for the differentiation between the beginning, middle, and end of menstruation mentioned in the book, it is necessary because if the maximum number of menstruation days is ten, and it is stated that at the beginning one must give a dinar, in the middle half a dinar, and at the end a quarter of a dinar, there must be a clear distinction among these periods. This distinction can only be made by dividing the days into three parts, as explained. Then, Shaykh (Al-Mufid), may Allah سبحانه وتعالى support him, stated: "If the menstrual blood stops, and a husband wishes to approach his wife, it is preferable for him to wait until she performs the ritual purification (ghusl) and then approach her. If he is overwhelmed by desire and finds it difficult to wait until she completes the purification, he should instruct her to wash her private area, after which he may approach her. There is no harm in this."
Commentary #18