حَدَّثَنَا عَبْدُ الرَّحْمَنِ ثَنَا مَالِكٌ عَنْ نَافِعٍ عَنِ ابْنِ عُمَرَ رَضِيَ اللَّهُ عَنْهُمَا أَنَّ النَّبِيَّ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ نَهَى عَنِ الشِّغَارِ قَالَ مَالِكٌ وَالشِّغَارُ أَنْ يَقُولَ أَنْكِحْنِي ابْنَتَكَ وَأُنْكِحُكَ ابْنَتِي
It is narrated from Sayyiduna Ibn Umar (may Allah be pleased with them both) that the Noble Prophet (peace and blessings be upon him) forbade the marriage of Shighar. Imam Malik says: Shighar is when a man says to another man: Marry your daughter to me and I will marry my daughter to you.