It was narrated from Ya'qub bin Aws, from a man among the Companions of the Prophet that:when the Messenger of Allah entered Makkah on the Day of the Conquest, he said: "Indeed, every accidental killing on purpose, or resembling on purpose - killing with a whip or stick, for it are forty (she-camels) which their young in their wombs."
أَخْبَرَنَا إِسْمَاعِيلُ بْنُ مَسْعُودٍ، قَالَ حَدَّثَنَا بِشْرُ بْنُ الْمُفَضَّلِ، عَنْ خَالِدٍ الْحَذَّاءِ، عَنِ الْقَاسِمِ بْنِ رَبِيعَةَ، عَنْ يَعْقُوبَ بْنِ أَوْسٍ، عَنْ رَجُلٍ، مِنْ أَصْحَابِ النَّبِيِّ صلى الله عليه وسلم أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم لَمَّا دَخَلَ مَكَّةَ يَوْمَ الْفَتْحِ قَالَ " أَلاَ وَإِنَّ كُلَّ قَتِيلِ خَطَإِ الْعَمْدِ أَوْ شِبْهِ الْعَمْدِ قَتِيلِ السَّوْطِ وَالْعَصَا مِنْهَا أَرْبَعُونَ فِي بُطُونِهَا أَوْلاَدُهَا " .
Nesai
The Book of Oaths (qasamah), Retaliation and Blood Money • Hadith 4796