Abu Mas`ud `Uqbah bin `Amr Al-Badri Al-Ansari (RadiyAllahu anhu) reported: Messenger of Allah (Sallellahu Alaihi Wa Sallam) said:
"The person who is best versed in the recitation of the Book of Allah, should lead the prayer; but if all those present are equally versed in it, then the one who has most knowledge of the Sunnah; if they are equal in that respect too, then the one who has emigrated (to Al-Madinah) first, if they are equal in this respect also, then the oldest of them. No man should lead another in prayer where the latter has authority, or sit in his house, without his permission". [Muslim].
In another narration in Muslim: Messenger of Allah (S.A.W.S.) said:
"One who is senior most in accepting Islam, should lead the Salat (prayer)". Yet another narration is: Messenger of Allah (S.A.W.S.) said:
"A man who is well versed in the Book of Allah and can recite it better, should lead the Salat (prayer); if (all those present) are equal in this respect, then the man who is senior most in respect of emigration, if they are equal in that respect too, then the oldest of them should lead the prayer".
This Hadith highlights the following three points:
1. The order of priority for the appointment of Imam [one who leads As-Salat (the prayers) should be as follows: First, preference should go to a good Qari (reciter of the Noble Qur'an) who is also an expert in it, provided he is pious and acts upon the teachings of the Noble Qur'an faithfully. He should not be a non-practising Muslim. Nowadays, we have an abundance of Imam but many of them are neither pious nor faithfully act upon religious teachings. In any case, where we can find a Qari who fulfills the requirements just mentioned, he deserves first preference for appointment as Imam. Even a religious scholar will come next to him. It must be borne in mind that nice recitation of the Noble Qur'an does not mean its recitation with great skill, but its essentials are elegant voice, acquaintance with the `Ilm-ut-Tajwid (or science of reciting the Qur'an), clear and distinct recitation.
2. The ruler of a territory, its highest officer and governor should work as Imam in their respective areas. In the early ages of Islam, these authorities used to administer their areas, dispense justice and lead congregational prayers (Salat).
3. When one goes to somebody's house, he should not occupy the place reserved for the master of the house unless he himself asks him to sit there.