قَالَ أَبُو بَكْرٍ: خَبَرُ النَّبِيِّ صَلَّى اللهُ عَلَيْهِ وَسَلَّمَ: «يَؤُمُّ الْقَوْمَ أَقْرَؤُهُمْ»
Imam Abu Bakr, may Allah have mercy on him, says that the evidence for this issue is the hadith of the Prophet Muhammad (peace be upon him) that the person who has memorized more of the Qur'an should lead the people in prayer (whether he is a son or a freed slave).