Ibn ‘Umar said “The Messenger of Allaah(ﷺ) prohibited shighar marriage. Musaddad added in his version “I said to ‘Nafi “What is shighar?” (It means that) a man marries the daughter of another man and gives his own daughter to him in marriage without fixing dower; and a man marries the sister of another man and gives him his sister in marriage without fixing dower.

حَدَّثَنَا الْقَعْنَبِيُّ، عَنْ مَالِكٍ، ح وَحَدَّثَنَا مُسَدَّدُ بْنُ مُسَرْهَدٍ، حَدَّثَنَا يَحْيَى، عَنْ عُبَيْدِ اللَّهِ، كِلاَهُمَا عَنْ نَافِعٍ، عَنِ ابْنِ عُمَرَ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم نَهَى عَنِ الشِّغَارِ ‏.‏ زَادَ مُسَدَّدٌ فِي حَدِيثِهِ قُلْتُ لِنَافِعٍ مَا الشِّغَارُ قَالَ يَنْكِحُ ابْنَةَ الرَّجُلِ وَيُنْكِحُهُ ابْنَتَهُ بِغَيْرِ صَدَاقٍ وَيَنْكِحُ أُخْتَ الرَّجُلِ وَيُنْكِحُهُ أُخْتَهُ بِغَيْرِ صَدَاقٍ ‏.‏