Sahih al-Bukhari 2164
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 `Abdullah:
حَدَّثَنَا مُسَدَّدٌ ، حَدَّثَنَا يَزِيدُ بْنُ زُرَيْعٍ ، قَالَ حَدَّثَنِي التَّيْمِيُّ ، عَنْ أَبِي عُثْمَانَ ، عَنْ عَبْدِ اللَّهِ ـ رضى الله عنه ـ قَالَ مَنِ اشْتَرَى مُحَفَّلَةً فَلْيَرُدَّ مَعَهَا صَاعًا. قَالَ وَنَهَى النَّبِيُّ صلى الله عليه وسلم عَنْ تَلَقِّي الْبُيُوعِ.
Whoever buys an animal which has been kept unmilked for a long time, could return it, but has to pay a Sa of dates along with it. And the Prophet (ﷺ) forbade meeting the owners of goods on the way away from the market.