The Obligatory Prayer Behind the One Performing a Voluntary Prayer or One Who Is in a State of Deficiency

Question:
Among the questions of Abu Badr, he says: A person who is praying a voluntary prayer was praying behind someone who was praying an obligatory prayer, and the obligatory prayer for that person was four rak'ahs. So he stood up and prayed two rak'ahs with him as the imam. He concluded the prayer after the two rak'ahs, then the person praying the obligatory prayer stood up and completed the prayer as four rak'ahs. What is the ruling on this action?

Answer:
It is permissible for one who shortens the prayer to pray behind one who completes it. When he concludes the prayer, he stands up and completes his prayer. Likewise, it is permissible for one who is praying an obligatory prayer to pray behind one who is praying a voluntary prayer, if the one praying the voluntary prayer is praying two rak'ahs. When he concludes the prayer, the one praying the obligatory prayer stands up and completes his prayer. Yes.

The presenter:
May Allah reward you,