1- Knowing other brothers, loving each other for the sake of Allah and strengthening ties of love; without which, perfect faith would not have been easy to achieve. This is because, there is no path to faith and paradise except by loving for the sake of Allah.
2- Freedom from hypocrisy and the hell fire. This is for someone who meets the initiating Takbeer of every Salat for forty consecutive days. Anas , reported the Messenger of Allah ﷺ as saying: “Whosoever observes Salat for Allah for forty days in congregation, catching the first Takbeer, has gained two freedoms, both of which are written for him: freedom from hell and freedom from hypocrisy.” [ Source: Al-Bukhari.]
3- Facilitating the reunion of Muslims and bringing their hearts together in goodness and righteousness.
4- Solidarity among the Muslims and helping one another in issues affecting them.
5- Demonstrating the religious rites and its strength.
6- Unifying the hearts of the Muslims, as in the same row of Salat there is gathered the White, Black, Arabs, non-Arabs, old, young, rich and the poor, side by side, in a single mosque, behind one imam, at the same time, towards the same direction and with the same intention.
7- Infuriating the enemies of Allah. This is because the Muslims will not cease to be powerful and invulnerable as long as they uphold the observation of congregational Salat in the mosque.
8- Eradication of misdeeds, and rising in ranks. It was reported on the authority of Abu Hurairah t, who reported that the Messenger of ﷺ said: “Should I direct you to that by which Allah eradicates sins and raises the levels?” They replied: “Yes, Oh Messenger of Allah.” Then the Prophet said: “Performing ablution when it is disliked, taking many steps to the mosques, and waiting for Salat one after the other. That is striving in the cause of Allah.” [ Source: Muslim.]
9- Observing Salat in congregation is better than observing it alone by twenty-seven degrees. On the authority of Abdullah ibn Umar t,, the Messenger of Allah ﷺ said: “Congregational Salah is better than that observed alone by twenty-seven degrees.” [ Source: Al-Bukhari.]
- Congregational Prayer (Salat ) at Home.
It is not advised for any individual or congregation to observe Salat at home while a mosque is close to them. However if the Mosque is far away, and they did not hear the call to prayer, then there is no sin on them if they observe it in congregation at home.