Wedlock, Marriage (Nikaah)
67/29. Chapter:
Ash-Shighar. (Exchange of daughters or sisters in marriage without paying Mahr)
Sahih Bukhari
حَدَّثَنَا عَبْدُ اللَّهِ بْنُ يُوسُفَ، أَخْبَرَنَا مَالِكٌ، عَنْ نَافِعٍ، عَنِ ابْنِ عُمَرَ ـ رضى الله عنهما ـ أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم نَهَى عَنِ الشِّغَارِ، وَالشِّغَارُ أَنْ يُزَوِّجَ الرَّجُلُ ابْنَتَهُ عَلَى أَنْ يُزَوِّجَهُ الآخَرُ ابْنَتَهُ، لَيْسَ بَيْنَهُمَا صَدَاقٌ.
Narrated Ibn `Umar: Allah's Messenger (ﷺ) forbade Ash-Shighar, which means that somebody marries his daughter to somebody else, and the latter marries his daughter to the former without paying Mahr.
Reference : Sahih al-Bukhari 5112In-book reference : Book 67, Hadith 49USC-MSA web (English) reference : Vol. 7, Book 62, Hadith 47