A traveler who did not pray Maghrib and 'Isha, then entered the mosque while the people were in the 'Isha prayer; what should he do?

The questioner : He says: A traveler did not pray Maghrib and 'Isha, then entered the Haram—for example—and the congregation was in the 'Isha prayer; what should he do? Should he pray 'Isha with them and then pray Maghrib?

The Shaykh : Yes, he should intend to pray behind the imam who is standing for the 'Isha prayer. He intends to pray the obligatory Maghrib prayer. If he catches the prayer behind the imam from the beginning, then when the imam stands for the fourth rak'ah, he intends to separate from him, sits for the final tashahhud, and says the taslim. By doing so, his obligatory prayer is Maghrib behind the imam who is praying 'Isha. Then he stands up and intends to pray 'Isha behind this imam. He may catch the rak'ah by catching the ruku', or he may not catch the ruku'. Wherever he catches the imam in this situation, he is obligated to follow him. When the imam says the taslim, he stands up and completes his prayer and his obligatory prayer, which is 'Isha.