Sahih Muslim Book - 19, Hadith - 3752

وَحَدَّثَنَا سَعِيدُ بْنُ مَنْصُورٍ وَقُتَيْبَةُ بْنُ سَعِيدٍ قَالاَ حَدَّثَنَا مَالِكٌ ح وَحَدَّثَنَا يَحْيَى بْنُ يَحْيَى - وَاللَّفْظُ لَهُ - قَالَ قُلْتُ لِمَالِكٍ حَدَّثَكَ نَافِعٌ عَنِ ابْنِ عُمَرَ أَنَّ رَجُلاً لاَعَنَ امْرَأَتَهُ عَلَى عَهْدِ رَسُولِ اللَّهِ -صلى الله عليه وسلم- فَفَرَّقَ رَسُولُ اللَّهِ -صلى الله عليه وسلم- بَيْنَهُمَا وَأَلْحَقَ الْوَلَدَ بِأُمِّهِ قَالَ نَعَمْ.

It was narrated from Ibn 'Umar that a man engaged in Li'an with his wife at the time of the Messenger of Allah (s.a.w), and the Messenger of Allah (s.a.w) separated them and attributed the child to his mother.