Sahih Muslim 5848
صحيح مسلم#5848Sahihوَحَدَّثَنَا مُحَمَّدُ بْنُ الصَّبَّاحِ، حَدَّثَنَا إِسْمَاعِيلُ يَعْنِي ابْنَ زَكَرِيَّاءَ، عَنْ سُهَيْلٍ، حَدَّثَتْنِي أُخْتِي، عَنْ أَبِي هُرَيْرَةَ، عَنِ النَّبِيِّ صلى الله عليه وسلم أَنَّهُ قَالَ " فِي أَوَّلِ ضَرْبَةٍ سَبْعِينَ حَسَنَةً " .
Abu Huraira reported Allah's Messenger (ﷺ) as saying (that he who kills a gecko) with the first stroke there are seventy rewards for him
Scholarly Authentication
The label above is the grade most of these scholars gave — one dissenting opinion no longer speaks for all of them. If any scholar calls a narration fabricated, that verdict is shown instead, whatever the others say. Each scholar's own wording:
Every narration in Sahih Muslim is accepted as Sahih (authentic) by the established status of the book.
In-book reference: 39:199