VERILY, [O you who believe in Me,] this community of yours is one single community, since I am the Sustainer of you all: worship, then, Me [alone]!
Al-Anbiya (The Prophets) Verse 92
The Prophet said, "The prayer in congregation is twenty five times superior to the prayer offered by person alone."
Sahih Bukhari: Volume 1, Book 11, Number 619