[Machine] The messenger of Allah ﷺ used to send someone after them if they bought food from the merchants, to prevent them from selling it until they reached their caravans.
أَنَّ رَسُولَ اللهِ ﷺ كَانَ يَبْعَثُ عَلَيْهِمْ إِذَا ابْتَاعُوا مِنَ الرُّكْبَانِ الْأَطْعِمَةَ مَنْ يَمْنَعُهُمْ أَنْ يَتَبَايَعُوهَا حَتَّى يُؤْوُوا إِلَى رِحَالِهِمْ