Chapter on Rulings on Forgetfulness (Sahw) in Prayer and What Requires Repeating of Prayer

Sa‘d, from Ahmad bin Muhammad, from Muhammad bin Abi Umayr, from Hammad bin ‘Uthman, from ‘Ubaydallah bin Ali al-Halabi; and al-Husayn bin Sa‘id, from Ali bin al-Nu‘man, from Abu al-Sabbah al-Kinani; and Ahmad bin Muhammad bin Abi Nasr, from al-Muthanna al-Hannat, from Abu Basir, all from Abu Abdillah عليه السلام, peace be upon him: Abu Abdillah عليه السلام (said) regarding a man who, in an obligatory prayer (‘al-maktubah’), begins reciting from the middle of a surah, then forgets and begins another surah until he completes it, and then remembers before going into ‘ruku’. Imam عليه السلام said: "He should go into ‘ruku’, and it does not harm him."