Nafi narrated to me that 'Abdullah said that Messenger of Allah 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 of a 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, the marriage is valid but its condition is illegal." The same scholar said regarding Al-Mut'a, "The marriage is invalid and its condition is illegal." Some others said, "The Mut'a and the Shighar are permissible but the condition is illegal."  

أَنَّ رَسُولَ اللَّهِ ﷺ نَهَى عَنِ الشِّغَارِ قُلْتُ لِنَافِعٍ مَا الشِّغَارُ قَالَ يَنْكِحُ ابْنَةَ الرَّجُلِ وَيُنْكِحُهُ ابْنَتَهُ بِغَيْرِ صَدَاقٍ وَيَنْكِحُ أُخْتَ الرَّجُلِ وَيُنْكِحُهُ أُخْتَهُ بِغَيْرِ صَدَاقٍ وَقَالَ بَعْضُ النَّاسِ إِنِ احْتَالَ حَتَّى تَزَوَّجَ عَلَى الشِّغَارِ فَهْوَ جَائِزٌ وَالشَّرْطُ بَاطِلٌ وَقَالَ فِي الْمُتْعَةِ النِّكَاحُ فَاسِدٌ وَالشَّرْطُ بَاطِلٌ وَقَالَ بَعْضُهُمُ الْمُتْعَةُ وَالشِّغَارُ جَائِزٌ وَالشَّرْطُ بَاطِلٌ