Imam Muhammad ibn Abdul Wahhab
Members of the Advisory Council of Umar, radiyallahu anhu, the second Caliph of Islam, were always the Ulamaa' (the learned in religion) whether they are old or of young age. Abu Huraira, radiyallahu anhu, reported that the Messenger of Allah, sallallahu alayhi wa sallam, said: Anyone who is most versed in Allah's Book should act as an Imam for the people; but if they are equally versed in reciting it, then the one who has most knowledge regarding the Sunna; if they are equal regarding the Sunna, then the earliest of them to emigrate; if they emigrated at the same time, then the oldest of them.
In another version it is reported: 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. Muslim transmitted it.
Jaabir radiyallahu anhu said: Allah's Messenger, sallallahu alayhi wa sallam, had each pair of those killed at the Ghazwa of Uhud wrapped in a single garment and asked which of them knew more of the Holy Quran. When one of them was pointed out to him, he had him put first in the side of the grave. Bukhari transmitted it.
Abu Musa Ashari radiyallahu anhu reported Allah's Messenger, sallallahu alayhi wa sallam, as saying: The respect of a Muslim who is of an old age and a follower of the Quran leads to the pleasure of Allah provided the follower of the Quran is not a transgressor and unfaithful to the Holy Quran.