Sahih Muslim Book 4, Hadith Number 1257.

Chapter : Desirability of going to prayer with dignity and tranquillity and forbiddance of going to it in hot haste.

Abu Salama reported Abu Huraira as saying: Iqama was pronounced. ant the people had formed themselves into rows. The Messenger of Allah (may peace be upon him) came out and stood at his place, and then pointed out with his hand that we should stand at our places. He then went away and took a bath and water trickled from his head and then led them in prayer.