And [Joseph] said to his servants, "Put their merchandise1 into their saddlebags so they might recognize it when they have gone back to their people that perhaps they will [again] return."
Translation: Saheeh International (English)
1 The goods which they had brought to trade for food supplies.
Joseph told his servants to return the merchandise of these people to them, so that they would realize on their return that they did not do trade with it, which would force them to return again with their brother, to prove their integrity to Joseph, and so that he would receive their merchandise from them.