Hadith #402
English (English)Whoever kills a lizard or a gecko with the first strike will have 100 virtues recorded for him; and less with the second strike, and lesser with the third strike.
Reference: صحیح مسلم، كتاب البر والصلة والآداب، باب النهي عن لعن الدواب وغيرها، الحدیث 2240