Abu Hurairah (ra) narrated that the Messenger of Allah صلى الله عليه وسلم said, “On Friday the Angels stand oust the door of the masjid and write down the names of the people in the order in which they enter the mosque for Friday prayer. The first group of people who enter the mosque get the reward equivalent to that of sacrificing a camel, the people who enter the mosque after them get the reward equivalent to that of sacrificing a cow. The people who enter the mosque after them get the reward equivalent to that of sacrificing a ram and the people who follow on likewise get this reward of a Chicken, egg and so on there is a gradation of rewards for the people as they enter. The angels keep writing the names of the people as they enter the mosque until the Imam sits down to give Khutbah. Then the angels collect their registers and sit and listen to the Khutbah.”

Bukhari, Muslim