What is the ruling if the Maghrib prayer time passes while traveling, and one arrives at the mosque and attends the 'Isha' prayer?

The questioner : O Shaykh, if the Maghrib prayer time passes while traveling or something similar, and I come to the mosque and attend the 'Isha' prayer, do I enter intending Maghrib or...?

The Shaykh : It is obligatory to have this intention; it is obligatory to pray Maghrib before 'Isha'. If you catch up with the imam in the first rak'ah, and then he stands up for the fourth rak'ah, you intend to separate from him, sit in the third rak'ah, recite the tashahhud, and say the taslim. Then you stand up and catch up with the imam, either in the last part of the fourth rak'ah of the 'Isha' prayer. In this case, you intend to pray 'Isha' with the imam. In any case, wherever you catch up with the imam, you intend to pray 'Isha'. When the imam says the taslim, you stand up and complete your prayer. Is that clear?