Narrated `Abdullah bin `Umar
Allah's Messenger (ﷺ) said, "Do not urge somebody to return what he has already bought (i.e. in optional sale) from another seller so as to sell him your own goods."
Narrated Abu Huraira
Allah's Messenger (ﷺ) forbade the selling of things by a town dweller on behalf of a desert dweller; and similarly Najsh was forbidden. And one should not urge somebody to return the goods to the seller so as to sell him his own goods; nor should one demand the hand of a girl who has already been engaged to someone else; and a woman should not try to cause some other woman to be divorced in order to take her place.