Musannaf Ibn Abi Shaybah 9104 — Where the row begins

Ibrahim said: The row begins in line with the imam. If there is only one man with the imam, the imam keeps him standing behind him until he bows. If another person comes, the imam leads him in prayer as well. If no one comes by the time the imam bows, the man standing behind joins the imam and stands on his right. If a man comes to pray and the row is complete, he should stand in line with the imam; if another person comes, he prays with him. If no one else comes, he should enter the row. Then the whole sequence continues in the same way.