حَدَّثَنَا الرَّبِيعُ بْنُ نَافِعٍ أَبُو تَوْبَةَ، حَدَّثَنَا مُحَمَّدُ بْنُ مُهَاجِرٍ، عَنْ أَبِيهِ، عَنْ أَسْمَاءَ بِنْتِ يَزِيدَ بْنِ السَّكَنِ، قَالَتْ سَمِعْتُ رَسُولَ اللَّهِ صلى الله عليه وسلم يَقُولُ ‏"‏ لاَ تَقْتُلُوا أَوْلاَدَكُمْ سِرًّا فَإِنَّ الْغَيْلَ يُدْرِكُ الْفَارِسَ فَيُدَعْثِرُهُ عَنْ فَرَسِهِ ‏"‏ ‏.‏

Narrated Asma', daughter of Yazid ibn as-Sakan,: I heard the Messenger of Allah (PBUH) as saying: Do not kill your children secretly, for the milk, with which a child is suckled while his mother is pregnant, overtakes the horseman and throws him from his horse. Translation Not Available

Book Ref: Sunan Abi Dawud Book 29 Hadith 3881
Web Ref:  Sunan Abi Dawud Book 28 Hadith 3872