The one who is the most versed in Allah's Book should lead the people in prayer
Authentic hadithعن أبي مسعود الأنصاري رضي الله عنه قال: قال رسول الله صلى الله عليه وسلم : «يَؤُمُّ القوم أقرؤهم لكتاب الله، فإن كانوا في القراءة سواء، فأعلمهم بالسنة، فإن كانوا في السنة سواء، فأقدمهم هجرة، فإن كانوا في الهجرة سواء، فأقدمهم سِلْمًا، ولا يَؤُمَّنَّ الرجل الرجل في سلطانه، ولا يقعد في بيته على تَكْرِمَتِهِ إلا بإذنه».
Abu Mas‘ūd al-Ansāri (may Allah be pleased with him) reported that the Messenger of Allah (may Allah's peace and blessings be upon him) said: “The one who is the most versed in Allah's Book should lead the people in prayer. If they are equally versed in reciting it, then the one who is the most knowledgeable about the Sunnah; and if they are equal regarding the Sunnah, then the earliest one to emigrate; if 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 in his house without his permission.”
Explanation
The Hadīth highlights some points: 1. The one who is the most entitled to leading the people in prayer is the one with the best memorization of the Qur'an. Yet, he has to be knowledgeable about the rulings pertaining to the prayer, since the one who is ignorant about such rulings has no right to lead the people in prayer. If they are equal in this point, the one who is the most knowledgeable about the Sunnah should lead them in prayer. If they are equal in this point too, then the one who is the earliest in immigrating should do. If they are still equal in this point, then the one who is the first among them to embrace Islam should lead them. 2. A guest should not precede the house owner in leading the people in prayer except with the latter’s permission. The house owner has more right to assume this task than the guest. 3. A guest is not allowed to sit in the house owner’s private place except with his permission.
Source · Narrated by Muslim
From the Hadith Encyclopedia (hadeethenc.com).