Sahih al-Bukhari 936
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)
حَدَّثَنَا مُعَاوِيَةُ بْنُ عَمْرٍو، قَالَ حَدَّثَنَا زَائِدَةُ، عَنْ حُصَيْنٍ، عَنْ سَالِمِ بْنِ أَبِي الْجَعْدِ، قَالَ حَدَّثَنَا جَابِرُ بْنُ عَبْدِ اللَّهِ، قَالَ بَيْنَمَا نَحْنُ نُصَلِّي مَعَ النَّبِيِّ صلى الله عليه وسلم إِذْ أَقْبَلَتْ عِيرٌ تَحْمِلُ طَعَامًا، فَالْتَفَتُوا إِلَيْهَا حَتَّى مَا بَقِيَ مَعَ النَّبِيِّ صلى الله عليه وسلم إِلاَّ اثْنَا عَشَرَ رَجُلاً، فَنَزَلَتْ هَذِهِ الآيَةُ ‏{‏وَإِذَا رَأَوْا تِجَارَةً أَوْ لَهْوًا انْفَضُّوا إِلَيْهَا وَتَرَكُوكَ قَائِمًا‏}‏