Ruling on the imam advancing if there is no space for the ma'mum to return

Q: There were two people in congregational prayer, and a third person joined them after they had already entered the prayer. The imam advanced because there was no space behind him for one of the two men to return. Is it permissible for the imam to advance, especially since we know from the hadith that the Messenger of Allah (peace and blessings be upon him) directed that one of the two should stay behind and the imam should not advance?

A: If the imam is in a position where he can pray and the two can stay behind him, they should stay behind and pray behind him. However, if the imam is in a position where it is not possible for them to stay behind him, he should advance, and there is no blame on him. In any case, the prescribed practice in such a matter is for the two men to be behind him, whether he advances or they stay behind him. If they all pray in one row, with both of them to his right, or one to his right and the other to his left, the prayer is valid, but they have left the preferred practice. It is established from the Prophet (peace and blessings be upon him) that he was praying alone when Jabir and Jibair came and stood to his right and left. He moved them back and placed them behind him. Similarly, in his story with Anas and the orphan, he placed them behind him.