Sahih Muslim Book 4, Hadith Number 1426.

Chapter : Excellence of sitting at the place of worship after the dawn prayer and excellence of the mosque.

Malik b Huwairith reported: I came to the Apostle of Allah (may peace be upon him) along with a companion of mine, and when we intended to return from him, he said: When there is time for prayer, announce prayer, pronounce Iqama, and the oldest amongst you should lead the prayer.