(4) باب الْحِيلَةِ فِي النِّكَاحِ
Narrated 'Abdullah:
Nafi narrated to me that 'Abdullah said that Allah's Messenger (ﷺ) forbade the Shighar. I asked Nafi', "What is the Shighar?" He said, "It is to marry the daughter of a man and marry one's daughter to that man (at the same time) without Mahr (in both cases); or to marry the sister ofa man and marry one's own sister to that man without Mahr." Some people said, "If one, by a trick, marries on the basis of Shighar, themarriage is valid but its condition is illegal." The same scholar saidregarding Al-Mut'a, "The marriage is invalid and its condition is illegal." Some others said, "The Mut'a and the Shighar are permissiblebut the condition is illegal."
Reference: Sahih al-Bukhari 6960
In-book reference: Book 90, Hadith 7
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 9, Book 86, Hadith 90