this congregation and his joining the second from its beginning, for joining a congregation from its beginning is preferable, as indicated in what has been reported about joining it in full. If the two congregations are otherwise equal, the second is preferable. If, however, the first is distinguished by its fuller merit, its greater numbers, the excellence of its imam, or its being the regularly established congregation, then it is preferable in that respect, whereas the second is preferable because one joins it in full. Sometimes one consideration may outweigh the other, and sometimes the reverse.

If, however, the second congregation is more complete in its performance of the prayer, or superior in its imam or congregation, then it has an additional advantage. An issue of this kind was not known among the early generations except when someone could catch the prayer at another mosque, since there were not two regular imams leading prayers in the same mosque, and the congregation would assemble in full behind the regular imam. Undoubtedly, praying in congregation with the mosque’s regular imam, even for one rakʿah, is better than praying at home, even in congregation. And Allah knows best.

He was asked:

Concerning a man who has performed his obligatory prayer, then comes to a congregational mosque and finds the people praying: may he pray with the congregation to make up a missed prayer?

He replied:

If a man has performed the obligatory prayer, then comes to a mosque where that is being offered