Chapter on the Virtue of Mosques and Prayer Within Them, and the Virtue of Congregational Prayer and Its Rulings

From him, from Ali ibn al-Nu‘man from al-Husayn ibn Abi al-A‘la from Abu Abdillah عليه السلام, peace be upon him, who said: I asked Imam al-Sadiq عليه السلام: “I come to the imam (of prayer) and he has preceded me by one rak‘ah in the dawn prayer. When he gave the taslim, it occurred to my heart that I had completed the prayer, so I remained remembering Allah سبحانه وتعالى, Mighty and Majestic, until the sun rose. When it rose, I stood up and remembered that the imam (of prayer) had preceded me by one rak‘ah.” Imam عليه السلام said: “If you are still in your place, then complete the prayer with one rak‘ah; but if you have already left (the place of prayer), then you must repeat the prayer.”