As long as the time for Isha is not due, you can delay it.

How long can I delay sunnah of Magrib salah, for it has limited time, and I do zikir (three Kul, Ayatal Kursi and tasbi) and it takes me up to 10 minutes.

Prayer | March 26, 2014 7:05 am
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It is right to say “Wal-Mumineen” or “Wal-Muslimin” in our Salah, when we invoke Allah? Because every Mumin is a Muslim but every Muslim is not Mumin-so can we pray for every Muslim while they are not good Muslims.
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How should one recite fatiha behind the imam what are the correct methods to do this. Can one recite with the imam when he is reciting also etc.