Messenger of Allah 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.
نَهَى رَسُولُ اللَّهِ ﷺ أَنْ يَبِيعَ حَاضِرٌ لِبَادٍ وَلاَ تَنَاجَشُوا وَلاَ يَبِيعُ الرَّجُلُ عَلَى بَيْعِ أَخِيهِ وَلاَ يَخْطُبُ عَلَى خِطْبَةِ أَخِيهِ وَلاَ تَسْأَلُ الْمَرْأَةُ طَلاَقَ أُخْتِهَا لِتَكْفَأَ مَا فِي إِنَائِهَا