(8) باب مَا لاَ يَجُوزُ مِنَ الشُّرُوطِ فِي النِّكَاحِ
Narrated Abu Huraira:
The Prophet (ﷺ) said, "No town-dweller should sell for a bedouin. Do not practice Najsh (i.e. Do not offer a high price for a thing which you do not want to buy, in order to deceive the people). No Muslim should offer more for a thing already bought by his Muslim brother, nor should he demand the hand of a girl already engaged to another Muslim. A Muslim woman shall not try to bring about The divorce of her sister (i.e. another Muslim woman) in order to take her place herself."
Reference: Sahih al-Bukhari 2723
In-book reference: Book 54, Hadith 12
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 3, Book 50, Hadith 884