Making dhikr in itself is a rewardable act, whether it occurs in the mosque or not. The exception here is the dhikr that is reported to be restricted to the mosque, such as making dhikr after Fajr Prayer till the sunrise, which, if followed by two rak`ahs, yields a reward similar to that gained by performing both Hajj and `Umrah. However, staying in the mosque entitles one to a great reward, which would be added to the reward gained by making dhikr.
In his work Nayl Al-Awtar, Imam Ash-Shawkani states: The reports indicating that the Prophet (peace and blessings be upon him) used to stay in his place for a while after finishing the Prayer—so as to give women the chance to leave the mosque—imply that leaving the mosque quickly is the established ruling. Some scholars argued against this ruling, citing the traditions that recommend making dhikr following the Prayers. However, it is clear that making dhikr after the Prayer does not necessitate staying in the mosque, except for those adhkar [plural of dhikr] that are reported to be made in the mosque; for example, the dhikr that should be said while “one’s knees are still bent.”

Imam An-Nawawi said in his book Al-Majmu`:

Some traditions were reported as regards making dhikr after Fajr Prayer:

  • Abu Dharr narrated that the Prophet (peace and blessings be upon him) said, “Whoever says after each Fajr Prayer, while his knees are still bent, ‘There is no god but Allah, the One and Only! There is no partner with Him, to Him belongs the sovereignty and to Him is the praise. He has the power to cause death and give life. He has power over all things!’ ten times, ten good deeds will be recorded for him, and ten sins will be erased. He will be exalted ten ranks and will be guarded against any trouble and against Satan for the whole day” (At-Tirmidhi).
  • Anas narrated that the Prophet (peace and blessings be upon him) said: “Whoever performs Fajr Prayer in a congregation, then he sits down, making dhikr until the sun rises, and then he makes two rak`ahs of Prayer, his reward will be equal to that of performing perfect, perfect, perfect Hajj and `Umrah.”

Shedding more light on the subject, Ibn Qudamah said in Al-Mughni:

If the congregation was composed of both men and women, the imam and the worshipers are recommended to stay in their places to enable women to leave the mosque. Women, on their part, should leave quickly after finishing the Prayer. Al-Bukahari reported Umm Salamah as saying, “During the Prophet’s lifetime, women used to leave the mosque once the Prophet had finished the Prayer. The Prophet and men used to stay for a while. Then, when the Prophet stood up, men did so.” Az-Zuhri said, “I believe this act was meant to let women walk for a long distance away from the mosque.”
In fact, paying no heed to this point would lead to the mixing of men and women. However, if there is no women attending the Prayer, the imam is recommended not to stay for a long period. `A’ishah reported: When the Messenger of Allah (peace and blessings be upon him) pronounced salutation, he used not to sit longer than it took him to say: “O Allah: You are Peace, and peace comes from You, blessed are You, O Possessor of Glory and Honor” (Ibn Majah).

Moreover, Al-Bara’ reported: I noticed the Prayer of the Messenger of Allah (peace and blessings be upon him) and saw his standing, his bowing, and then going back to the standing posture after bowing, his prostration, his sitting between the two prostrations, and his prostration and sitting between salutation and going away, all these were nearly equal to one another.
The narration of Al-Bukhari goes as follows: The bowing, the prostration, the sitting in between the two prostrations, and the standing after the bowing of the Prophet but not qiyam (standing in the Prayer) and qu`ud (sitting in the Prayer) used to be approximately equal (in duration).
Also, Jabir ibn Samurah reported that when the Messenger of Allah observed the Dawn Prayer, he sat at the place of worship till the sun had risen enough.
The attendants of the congregational Prayer are recommended not to leave before the imam, since he might remember something wrong, he did in the Prayer, which requires making sujud as-sahw (two prostrations meant to made up for mistakes in the Prayer). The Prophet (peace and blessings be upon him) said, “I am your imam, so do not precede me in bowing and prostration and in standing and leaving.” However, if the imam did not abide by the Sunnah and stayed for a long time in his place, there is no wrong on the part of the worshipers to leave the mosque before him.