Sahih al-Bukhari 2162
Sahih al-Bukhari · Book 34: Sales and Trade · It is forbidden to meet the caravans on the way (to buy the goods away from the market)
Narrated Abu Huraira:
حَدَّثَنَا مُحَمَّدُ بْنُ بَشَّارٍ ، حَدَّثَنَا عَبْدُ الْوَهَّابِ ، حَدَّثَنَا عُبَيْدُ اللَّهِ ، عَنْ سَعِيدِ بْنِ أَبِي سَعِيدٍ ، عَنْ أَبِي هُرَيْرَةَ ـ رضى الله عنه ـ قَالَ نَهَى النَّبِيُّ صلى الله عليه وسلم عَنِ التَّلَقِّي، وَأَنْ يَبِيعَ حَاضِرٌ لِبَادٍ.
The Prophet (ﷺ) forbade the meeting (of caravans) on the way and the selling of goods by an inhabitant of the town on behalf of a desert dweller.