(1) “Made obligatory”: thus in H and B; all other manuscripts read: “became obligatory.” (2) “Thus, if”: thus in A and B; all other manuscripts read: “and if.” (3) “If” is omitted from N, M, A, and Y. W reads: “whoever does not perform.” (4) H and B read: “what was commanded, by completing the obligatory act.” (5) I could not find the hadith with this wording. It is, however, narrated from Alī ibn Shaybān—may Allah be pleased with him—in *Sunan Ibn Mājah*, 1/320, Book of Establishing Prayer, chapter “A Man Praying Alone behind the Row.” Its wording is: “We set out until we came to the Prophet—may Allah bless him and grant him peace—pledged allegiance to him, and prayed behind him. We then prayed another prayer behind him. When he had finished the prayer, he saw a man praying alone behind the row. The narrator said: When the Prophet of Allah—may Allah bless him and grant him peace—had turned away, he stood before him and said, ‘Begin your prayer anew, for there is no prayer for one who prays behind the row.’” The note in *al-Zawā’id* states: “Its chain of transmission is sound, and its narrators are trustworthy.” The hadith is also found in *al-Musnad*, al-Halabī ed., 4/23, and *Mawārid al-Zam’ān ilā Zawā’id Ibn Hibbān*, p. 116, hadith nos. 401–402, al-Salafiyya ed. Al-Albānī authenticated it in *Sahīh al-Jāmi’ al-Saghīr*, 1/322, and *Irwā’ al-Ghalīl*, 2/328–329. He discussed at length the prayer of one who stands alone behind the row, 2/323–330, as well as the hadith of Wābisa ibn Ma’bad, according to which the Prophet—may Allah bless him and grant him peace—saw a man praying behind the row and instructed him to repeat the prayer. That hadith is found in *Sunan Abī Dāwūd*, *Sunan al-Tirmidhī*, and *al-Musnad*.