The ruling on the prayer of one who enters behind a person praying the voluntary prayer after Maghrib

Question:
After this message, we received one from a brother listener, a brother in Allah named Alif 'Ayn. He asks: How should I act if I am praying the two rak'ahs of the voluntary prayer after Maghrib, and a person comes to pray behind me, becoming a follower while believing that I am praying an obligatory prayer? Perhaps his intention is to pray beside me, meaning he cannot pray behind me while I am praying alone. That is what he wrote. Yes, that is right. Meaning he follows me and then moves to my side. Yes. Yes.

Answer:
The default ruling in this matter is that the one who joins late does not follow, nor does he pray a voluntary prayer. This is based on the action of Mu'adh (may Allah be pleased with him) during the time of the Prophet (peace and blessings be upon him). He used to pray with the Prophet (peace and blessings be upon him) while traveling, then he would stand up, go out, and pray with his people. He had a voluntary prayer and he had a Muslimah. Yes.
This indicates the validity of the major sins of the Fajr prayer. As for this person who came while you were praying a voluntary prayer before Maghrib and prayed behind you, and you did not pray Maghrib, this is considered an error on his part. If he completed the prayer with you and finished the prayer, then if he prayed and completed the rest of the prayer, his prayer is valid. However, the issue here is that he prayed before the congregation was established.
It would have been better for him to pray with the congregation. So, this means his action was beneficial in that he intended an obligatory prayer while you were praying a voluntary one, but he erred in that he prayed before the congregation was prayed. Perhaps he found that some people had already prayed, so this would be an excuse for him in that matter. As for his prayer...