Verily, those who have attained to faith and do good works, and are constant in prayer, and dispense charity - they shall have their reward with their Sustainer, and no fear need they have, and neither shall they grieve.
Al-Baqara (The Cow) Verse 277
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