Sunnan Abu Dawud Collection: ::Book Number 10:: Hadith # 1730
Narrated Abdullah ibn Abbas: The people used to trade, in the beginning, at Mina, Arafat, the market place of Dhul-Majaz, and during the season of hajj. But (later on) they became afraid of trading while they were putting on ihram. So Allah, glory be to Him, sent down this verse: "It is no sin for you that you seek the bounty of your Lord during the seasons of hajj." Ubayd ibn Umayr told me that he (Ibn Abbas) used to recite this verse in his codex.