Sahih al-Bukhari 5315
Sahih al-Bukhari · Book 68: Divorce · The child is to be given to the lady (accused by her husband).
Narrated Ibn `Umar:
حَدَّثَنَا يَحْيَى بْنُ بُكَيْرٍ ، حَدَّثَنَا مَالِكٌ ، قَالَ حَدَّثَنِي نَافِعٌ ، عَنِ ابْنِ عُمَرَ ، أَنَّ النَّبِيَّ صلى الله عليه وسلم لاَعَنَ بَيْنَ رَجُلٍ وَامْرَأَتِهِ، فَانْتَفَى مِنْ وَلَدِهَا فَفَرَّقَ بَيْنَهُمَا، وَأَلْحَقَ الْوَلَدَ بِالْمَرْأَةِ.
The Prophet (ﷺ) made a man and his wife carry out Lian, and the husband repudiated her child. So the Prophet got them separated (by divorce) and decided that the child belonged to the mother only.