He did not pray Maghrib while the Isha Prayer had already begun
Question:
I entered the mosque when the Isha prayer had already begun. But before I joined them in the prayer, I remembered that I had not prayed the Maghrib prayer. (In such a case) should I perform the Maghrib prayer, and then catch what I can of the Isha Prayer in congregation, or should I perform the Maghrib prayer after that?
Answer:
If you entered the mosque while the Isha prayer was in progress, then you remembered that you had not prayed the Maghrib prayer, you should join the congregation with the intention of praying Maghrib, then when the Imam stands up for the fourth Rakah, you should remain sitting in the third Rakah, and wait until the Imam makes the Taslim and then make the Taslim with him. And there is no harm in the difference of intentions between the Imam and the one behind him, according to the most authoritative saying of the scholars. And if you prayed Maghrib alone and then joined what remained of the congregational prayer, there is no objection.
Shaykh `Abdul-`Azeez Bin Baz
Fatawa Islamiyah Vol. 2 Page 250
