Isa bin Yonus bin Abi Ishaq عيسى بن يونس بن أبي إسحاق · The Chapters on Marriage

she heard the Messenger of Allah say: "Do not kill your children secretly, for by the One in Whose Hand is my soul, intercourse with a breastfeeding woman catches up with people when they are riding their horses (in battle) and wrestles them to the ground."