Sunan an-Nasai 19242
In-book no 4506أَخْبَرَنَا قُتَيْبَةُ، عَنْ مَالِكٍ، عَنْ أَبِي الزِّنَادِ، عَنِ الأَعْرَجِ، عَنْ أَبِي هُرَيْرَةَ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ " لاَ تَلَقُّوا الرُّكْبَانَ لِلْبَيْعِ وَلاَ يَبِعْ بَعْضُكُمْ عَلَى بَيْعِ بَعْضٍ - وَلاَ تَنَاجَشُوا - وَلاَ يَبِيعُ حَاضِرٌ لِبَادٍ " .
It was narrated from Abu Hurairah that the Messenger of Allah said: "Do not go out to meet the riders, and do not urge someone to cancel a sale he has already agreed upon os as to sell him your own goods, do not artificially inflate prices, and let not a town-dweller sell for a desert-dweller." (Sahih )