How Long Should Those Praying Behind an Imam Wait Before Getting Up?

Imām Ibn Taimiyyah, may Allāh have mercy on him, said:

One being led by an imam [in congregational prayer] should not get up until the imam turns away, i.e., moves away from [facing] the qiblah. [At the same time], the imam should not remain seated facing the qiblah after [giving] the salām [to complete the prayer] other than the length of time it takes for him to seek forgiveness three times¹ and to say:² ³

   اللًّهُمَّ أَنْتَ السَّلامُ وَمِنْكَ السَّلامُ، تَبَارَكْتَ يَا ذَا الجَلَالِ وَالإِكْرَام

Then when the imam has moved [to face a different direction than the qiblah], whoever wants to get up, [can] get up, and whoever likes to stay seated remembering Allāh [through supplications and words of praise], [can] do that.

Majmūʿ Al-Fatāwá, vol. 22, p. 505.

¹i.e., saying أَسْتَغْفِرُ اللَّه three times (tr.)

²O Allāh, You are Al-Salām [the Ever-Secure from imperfection and harm, the Provider of all security] and from You is all security; ever-great You are, O Dha-l-Jalāl wa-l-Ikrām [You Who deserves to be exalted, loved, and glorified] (tr.)

³After fajr and maghrib prayers, the imam can also remain seated facing the qiblah, his feet and legs still in the position they were in during the final sitting of the prayer, to say the following ten times:

   لاَ إِلَهَ إِلَّا اللَّهُ وَحْدَهُ لَا شَرِيكَ لَهُ، لَهُ المُلْكُ وَلَهُ الحَمْدُ يُحْيِي وَيُمِيتُ وَهُوَ عَلَى كُلِّ شَيْءٍ قَدِيرٌ

There is nothing to be worshiped in truth except Allāh alone; no one shares [anything] with Him; to Him alone do all things belong and all decisions over them, and to Him alone is due all praise, filled with love and gratitude; He gives life, and He takes it, and He is over all things, All-Powerful.

See Shaikh Al-Albānī’s discussion in Silsilah Al-Hudá wa-l-Nūr, no. 15, 00:23:31. (Tr.)