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

Muhammad ibn Ali ibn Mahbub from Muhammad ibn Ahmad from al-Amraki from Ali ibn Ja’far who said: (Ali ibn Ja’far said) “I asked Imam Musa ibn Ja’far عليه السلام, peace be upon them both, about standing behind the imam (of prayer) in the row, what is its limit?” Imam عليه السلام said: “Stand as much as you are able, and if you sit and the space becomes tight, then move forward or backward, there is no problem.”