Abu Huraira reported God's messenger as saying, "We have not made peace with them 1 since we fought with them, so he who leaves any of them alone through fear does not belong to us." 1. i.e. snakes. Abu Dawud transmitted it.

وَعَنْ أَبِي هُرَيْرَةَ قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: «مَا سَالَمْنَاهُمْ مُنْذُ حَارَبْنَاهُمْ وَمَنْ تَرَكَ شَيْئًا مِنْهُمْ خِيفَةً فَلَيْسَ منَّا» . رَوَاهُ أَبُو دَاوُد