Sahih Muslim Book 4, Hadith Number 1420.

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

Abu Mas’ud al-Ansari reported Allah’s Messenger (may peace be upon him) as saying: The one who is most versed in Allah’s Book should act as Imam for the people, but If they are equally versed in reciting it, then the one who has most knowledge regarding Sunnah if they are equal regarding the Sunnah, then the earliest one to emigrate; it they emigrated at the same time, then the earliest one to embrace Islam. No man must lead another in prayer where (the latter) has authority, or sit in his place of honour in his house, without his permission. Ashajj in his narration used the word, “age” in place of “Islam”.