Establishing another jamaa’ah in the mosque
Question

Some brothers come late when the first jamaa’ah (congregation) has finished, so they pray in a second jamaa’ah with a different imam.
Praise be to Allah.This is the issue of establishing a second jamaa’ah in the mosque. The Standing Committee (7/309) was asked about the ruling on establishing a second jamaa’ah in the mosque and replied: 
Whoever comes to the mosque and finds that the jamaa’ah has prayed with the regular imam or another imam, should pray in jamaa’ah with others like him who also missed the (first) jamaa’ah, or some of those who have already prayed should do him the favour of praying with him, because of the hadeeth narrated by Ahmad in his Musnad, and by Abu Dawood in his Sunan, from Abu Sa’eed al-Khudri (may Allah be pleased with him) who said that the Messenger of Allah (peace and blessings of Allah be upon him) saw a man praying by himself and said, “Won’t someone do this man a favour and pray with him?” So a man got up and prayed with him. Al-Tirmidhi also narrated this from Abu Sa’eed al-Khudri (may Allah be pleased with him), but he said, “So a man came and prayed with him.” 
Al-Tirmidhi said: (it is) a hasan hadeeth. It was also narrated and classed as saheeh by al-Haakim, and al-Dhahabi agreed with him. It was also narrated by Ibn Hazm in al-Muhalla, and he indicated that it is saheeh. 
Abu ‘Eesa al-Tirmidhi said: This is the view of more than one of the Sahaabah and Taabi’een. They said: there is nothing wrong with people praying in congregation in a mosque in which a congregational prayer has already been offered. This was also the view of Ahmad and Ishaaq. 
Others said that they should pray individually. This was the view of Sufyaan, Ibn al-Mubaarak, Maalik and al-Shaafa’i. End quote. 
They and those who agreed with them regarded it as makrooh because they feared division and the generation of enmity, and that those who follow their whims and desires might take that as an excuse for coming late for prayers in congregation, so that they could pray in another jamaa’ah behind an imam who agreed with their deviant ways and innovations. So they blocked the way that leads to division and put an end to the aims of those who follow their evil whims and desires, by saying that no one should offer an obligatory prayer in congregation in a mosque when the prayer has already been offered in jamaa’ah with a regular imam or any other imam. 
The first opinion is the one which is correct, because of what we have said above about the general meaning of the verse (interpretation of the meaning): 
“So keep your duty to Allah and fear Him as much as you can”
[al-Taghaabun 64:16]
And the words of the Prophet (peace and blessings of Allah be upon him): “When I command you to do a thing, do as much of it as you can.” 
Undoubtedly praying in congregation is part of fearing Allah (taqwa) and is one of the things enjoined by sharee’ah, so we should strive to do it as much as we can. 
It is not right to contradict a sound narration with the opinions of some scholars who based their view repeating the jamaa’ah in the mosque as makrooh on their own rational thinking. Rather we should do that which is indicated by the saheeh reports. If it is known that a person or a group delays (joining the jamaa’ah) because of negligence, and does that repeatedly, or it is known from their behaviour or their affiliation with a different group that they are delaying in order to pray with others like them, they should be rebuked and they should be disciplined in whatever manner seems fit to those who are in charge, as a deterrent to them and others like them who follow their whims and desires. Thus the way to division will be barred and the aims of those who follow their whims and desires will be thwarted whilst also following the evidence which says that those who missed the first jamaa’ah should pray in another jamaa’ah. 
And Allah is the Source of strength. May Allah send blessings and peace upon our Prophet Muhammad and upon his family and companions. 
Al-Lajnah al-Daa’imah li’l-Buhooth al-‘Ilmiyyah wa’l-Ifta’ (Standing Committee for Academic Research and Issuing Fatwas). 
This is with regard to the five daily prayers. With regard to Jumu’ah (Friday) prayer, it should not be repeated, rather it ends with the imam’s salaam. Whoever misses Jumu’ah prayer should pray Zuhr instead, whether on his own or with a jamaa’ah. 
The above is with regard to the ruling. With regard to sin, if the person’s delay was for a legitimate shar’i excuse, then there is no sin on him, but if there was no excuse then it is a sin. 
See also the answers to question no. 26807.