Sahih Bukhari | Volume 3 | Hadith Number 330
Narrated by Abu Huraira
Allah's Apostle said, "The congregational prayer of anyone amongst you is more than twenty (five or twenty seven) times in reward than his prayer in the market or in his house, for if he performs ablution completely and then goes to the mosque with the sole intention of performing the prayer, and nothing urges him to proceed to the mosque except the prayer, then, on every step which he takes towards the mosque, he will be raised one degree or one of his sins will be forgiven. The angels will keep on asking Allah's forgiveness and blessings for everyone of you so long as he keeps sitting at his praying place. The angels will say, 'O Allah, bless him! O Allah, be merciful to him!' as long as he does not do Hadath or a thing which gives trouble to the other." The Prophet further said, "One is regarded in prayer so long as one is waiting for the prayer."