أَخْبَرَنَا مُحَمَّدُ بْنُ مَنْصُورٍ، قَالَ حَدَّثَنَا سُفْيَانُ، عَنْ أَبِي الزِّنَادِ، عَنِ الأَعْرَجِ، عَنْ أَبِي هُرَيْرَةَ، عَنِ النَّبِيِّ صلى الله عليه وسلم قَالَ ‏"‏ لاَ تَلَقُّوا الرُّكْبَانَ لِلْبَيْعِ وَلاَ تُصَرُّوا الإِبِلَ وَالْغَنَمَ مَنِ ابْتَاعَ مِنْ ذَلِكَ شَيْئًا فَهُوَ بِخَيْرِ النَّظَرَيْنِ فَإِنْ شَاءَ أَمْسَكَهَا وَإِنْ شَاءَ أَنْ يَرُدَّهَا رَدَّهَا وَمَعَهَا صَاعُ تَمْرٍ ‏"‏ ‏.‏

It was narrated from Abu Hurairah that the Prophet said

"Do not go out to meet the riders, and do not bind the udders of camels and seep. Whoever has boughty anything in that manner has two choices: If he whishes he may keep it, or if he wants to return it he may return it, along with a Sa of dates." (Sahih )