Sunan An-Nasa'i - سنن النسائي
27. The Book of Divorce - كتاب الطلاق
45) Chapter: Denying The Child Through Li'an, And Attributing Him To His Mother
It was narrated that Ibn 'Umar said:
"The Messenger of Allah conducted the procedure of Li'an between a man and his wife, and he separated them and attributed the child to his mother."
45) باب نَفْىِ الْوَلَدِ بِاللِّعَانِ وَإِلْحَاقِهِ بِأُمِّهِ
أَخْبَرَنَا قُتَيْبَةُ، قَالَ حَدَّثَنَا مَالِكٌ، عَنْ نَافِعٍ، عَنِ ابْنِ عُمَرَ، قَالَ لاَعَنَ رَسُولُ اللَّهِ صلى الله عليه وسلم بَيْنَ رَجُلٍ وَامْرَأَتِهِ وَفَرَّقَ بَيْنَهُمَا وَأَلْحَقَ الْوَلَدَ بِالأُمِّ .