"There is no sin on you if you ask the Bounty of your Lord (during pilgrimage by trading)..." (V.2:198) Sahih al-Bukhari 4519
Arabic hadith text
حَدَّثَنِي مُحَمَّدٌ، قَالَ أَخْبَرَنِي ابْنُ عُيَيْنَةَ، عَنْ عَمْرٍو، عَنِ ابْنِ عَبَّاسٍ ـ رضى الله عنهما ـ قَالَكَانَتْ عُكَاظٌ وَمَجَنَّةُ وَذُو الْمَجَازِ أَسْوَاقًا فِي الْجَاهِلِيَّةِ فَتَأَثَّمُوا أَنْ يَتَّجِرُوا فِي الْمَوَاسِمِ فَنَزَلَتْ {لَيْسَ عَلَيْكُمْ جُنَاحٌ أَنْ تَبْتَغُوا فَضْلاً مِنْ رَبِّكُمْ} فِي مَوَاسِمِ الْحَجِّ.
Translation
Narrated Ibn `Abbas
`Ukaz, Mijanna and Dhul-Majaz were markets during the Pre-islamic Period. They (i.e. Muslims) considered it a sin to trade there during the Hajj time (i.e. season), so this Verse was revealed:-- "There is no harm for you if you seek of the Bounty of your Lord during the Hajj season." (2.198)