"when there are three people let one of them lead the prayer, and the one who is most entitled to lead the prayer is the one who has most knowledge of the Qur'an."  

عَنِ النَّبِيِّ ﷺ قَالَ إِذَا كَانُوا ثَلاَثَةً فَلْيَؤُمَّهُمْ أَحَدُهُمْ وَأَحَقُّهُمْ بِالإِمَامَةِ أَقْرَؤُهُمْ