Sahih Bukhari Volume 3, Book 34, Hadith 2051

حَدَّثَنى عَبْدُ اللَّهِ بْنُ مُحَمَّدٍ، حَدَّثَنَا سُفْيَانُ، عَنْ عَمْرٍو، عَنِ ابْنِ عَبَّاسٍ ـ رضى الله عنهما ـ قَالَ كَانَتْ عُكَاظٌ وَمِجَنَّةُ وَذُو الْمَجَازِ أَسْوَاقًا فِي الْجَاهِلِيَّةِ، فَلَمَّا كَانَ الإِسْلاَمُ فَكَأَنَّهُمْ تَأَثَّمُوا فِيهِ فَنَزَلَتْ ‏{‏لَيْسَ عَلَيْكُمْ جُنَاحٌ أَنْ تَبْتَغُوا فَضْلاً مِنْ رَبِّكُمْ ‏}‏ فِي مَوَاسِمِ الْحَجِّ، قَرَأَهَا ابْنُ عَبَّاسٍ

Narrated By Ibn 'Abbas : 'Ukaz, Majanna and Dhul-Majaz were market-places in the Pre-Islamic period of ignorance. When Islam came, Muslims felt that marketing there might be a sin. So, the Divine Inspiration came: "There is no harm for you to seek the bounty of your Lord (in the seasons of Hajj)." (2.198) Ibn 'Abbas recited the Verse in this way.