Musnad Abu Ya'la al-Mawsili 155:318

Muhammad ibn Ishaq al-Musayyibi narrated to us, Anas ibn Iyad narrated to us, from Yunus, from Ibn Shihab: Abu Abdullah al-Agharr informed me that he witnessed Abu Hurairah saying: The Messenger of Allah (peace and blessings of Allah be upon him) said: "When it is the day of Friday, there are angels at every door of the mosque writing down the first [to arrive], then the first. When the Imam sits, they fold the scrolls and come to listen to the reminder (dhikr). The likeness of the one who arrives early is like the one who offers a camel as a sacrifice, then like the one who offers a cow, then like the one who offers a ram, then like the one who offers a chicken, then like the one who offers an egg."