Two people entered the mosque, and there was not enough space left in the front row for both of them, rather there was only enough space for one person. Is it better for one of them to stand in the front row and the other to stand in the second row on his own? Or should they stand together in the second row?.
If two people come in and they find that there is only enough room for one man in the first or second row, then they should stand together, because if one of them joins the row the other will be left standing on his own. In this case it is better for them to pray standing together behind the row. But if they find enough room for two men in the row, then they should both stand there, and not stand behind the row on their own, because that is contrary to the Sunnah. The Prophet (peace and blessings of Allaah be upon him) encouraged completing the rows one by one, starting with the first. But if it so happens that they did that, then their prayer is valid because neither of them stayed on his own away from the other. End quote.