Sahih Bukhari 640

Narrated Jabir bin `Abdullah: On the day of Al-Khandaq (the trench), `Umar bin Al-Khattab went to the Prophet and said, O Allah's Apostle! By Allah, I could not pray (the `Asr) till the sun had set. `Umar told this to the Prophet at the time..

Narrated Anas: Once the Iqama was pronounced and the Prophet was talking to a man (in a low voice) in a corner of the mosque and he did not lead the prayer till (some of) the people had slept (dozed in a sitting posture) . ..

Narrated Anas bin Malik: Once Iqama was pronounced a man came to the Prophet and detained him (from the prayer). ..

Narrated Abu Huraira: Allah's Apostle said, By Him in Whose Hand my soul is I was about to order for collecting firewood (fuel) and then order Someone to pronounce the Adhan for the prayer and then order someone to lead the prayer then I would go..

Narrated `Abdullah bin `Umar: Allah's Apostle said, The prayer in congregation is twenty seven times superior to the prayer offered by person alone. ..

Narrated Abu Sa`id Al-Khudri: The Prophet said, The prayer in congregation is twenty five times superior to the prayer offered by person alone. ..