(38) باب إِذَا نَفَرَ النَّاسُ عَنِ الإِمَامِ فِي صَلاَةِ الْجُمُعَةِ فَصَلاَةُ الإِمَامِ وَمَنْ بَقِيَ جَائِزَةٌ
Narrated Jabir bin `Abdullah:
While we were praying (Jumua Khutba & prayer) with the Prophet (p.b.u.h), some camels loaded with food, arrived (from Sham). The people diverted their attention towards the camels (and left the mosque), and only twelve persons remained with the Prophet. So this verse was revealed: "But when they see Some bargain or some amusement, They disperse headlong to it, And leave you standing." (62.11)
Reference: Sahih al-Bukhari 936
In-book reference: Book 11, Hadith 60
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 2, Book 13, Hadith 58