What is the ruling concerning the prayer of two young men who were led in prayer by a traveler, and who, being residents, completed their prayer in congregation after the Imam’s taslim? And is there any mention of this in Islamic law?

Scholars have differed on the ruling of a congregant following another congregant after the Imam has concluded the prayer. Some have prohibited it, while others have permitted it, and this is the ruling adopted by us and preferred by a group of verifyers. Some scholars consider it to be contrary to what is superior, and closer to innovation than to the Sunnah.