It is forbidden to meet the caravans on the way (to buy the goods away from the market) Sahih al-Bukhari 2162
Arabic hadith text
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 عَنِالتَّلَقِّي، وَأَنْ يَبِيعَ حَاضِرٌ لِبَادٍ.
Translation
Narrated Abu Huraira
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.