Sahih Bukhari Volume 2, Book 11, Hadith 930

حَدَّثَنَا آدَمُ، قَالَ حَدَّثَنَا ابْنُ أَبِي ذِئْبٍ، عَنِ الزُّهْرِيِّ، عَنْ أَبِي عَبْدِ اللَّهِ الأَغَرِّ، عَنْ أَبِي هُرَيْرَةَ، قَالَ قَالَ النَّبِيُّ صلى الله عليه وسلم ‏"‏ إِذَا كَانَ يَوْمُ الْجُمُعَةِ، وَقَفَتِ الْمَلاَئِكَةُ عَلَى باب الْمَسْجِدِ يَكْتُبُونَ الأَوَّلَ فَالأَوَّلَ، وَمَثَلُ الْمُهَجِّرِ كَمَثَلِ الَّذِي يُهْدِي بَدَنَةً، ثُمَّ كَالَّذِي يُهْدِي بَقَرَةً، ثُمَّ كَبْشًا، ثُمَّ دَجَاجَةً، ثُمَّ بَيْضَةً، فَإِذَا خَرَجَ الإِمَامُ طَوَوْا صُحُفَهُمْ، وَيَسْتَمِعُونَ الذِّكْرَ ‏"‏‏

Narrated By Abu Huraira : The Prophet said, "When it is a Friday, the angels stand at the gate of the mosque and keep on writing the names of the persons coming to the mosque in succession according to their arrivals. The example of the one who enters the mosque in the earliest hour is that of one offering a camel (in sacrifice). The one coming next is like one offering a cow and then a ram and then a chicken and then an egg respectively. When the Imam comes out (for Jumua prayer) they (i.e. angels) fold their papers and listen to the Khutba."