It was narrated from Ya'qub bin Aws that:

a man from among the Companions of the Prophet narrated to him that the Prophet entered Makkah during the Year of the Conquest, and said: 'Indeed, accidental killing on purpose, is killing with a whip or stick, for which forty (she-camels) with their young in their wombs."

أَخْبَرَنَا مُحَمَّدُ بْنُ عَبْدِ اللَّهِ بْنِ بَزِيعٍ، قَالَ أَنْبَأَنَا يَزِيدُ، عَنْ خَالِدٍ، عَنِ الْقَاسِمِ بْنِ رَبِيعَةَ، عَنْ يَعْقُوبَ بْنِ أَوْسٍ، أَنَّ رَجُلاً، مِنْ أَصْحَابِ النَّبِيِّ ﷺ حَدَّثَهُ أَنَّ النَّبِيَّ ﷺ دَخَلَ مَكَّةَ عَامَ الْفَتْحِ قَالَ " أَلاَ وَإِنَّ قَتِيلَ الْخَطَإِ الْعَمْدِ قَتِيلَ السَّوْطِ وَالْعَصَا مِنْهَا أَرْبَعُونَ فِي بُطُونِهَا أَوْلاَدُهَا " .