virtue of salat in jammah congregation

Allah SWT says: And establish salat and give Zakat; and bow with those who bow in worship (i.e. pray in congregation) (al-baqarah 2:43)

Abu Hurarirah RA narrated that Nabi SAW said: The muadhdhin will receive forgiveness to the distance to which his voice reaches. All living and non-living things shall bear witness for him on the Day of Resurrection. He, who attends salat in congregation, for him is written the reward of twenty five salat, and it becomes an atonement for his sins between two Salat. (Abu Dawud)
Note: According to some Scholars the reward of twenty-five Salat is for the muadhdhin, and he gets forgiveness of his sins from the previous Adhan to this Adhan. (Badhl-ul-Majhud)

Ibne Umar RA narrates that Nabi SAW said: He who calls the Adhan for twelve years, Paradise is guaranteed for him and sixty blessings will be recorded for every adhan, thirty blessings will be recorded for every Iqamah. (Mustadrak Hakim)