Bulugh al-Maram, Book 1, Hadith 88 (In-Book) ⓘ

and Al-Bukhari said, “It is the most authentic in this chapter”.

وَقَالَ اَلْبُخَارِيُّ: هُوَ أَصَحُّ شَيْءٍ فِي هَذَا اَلْبَابِ.‏

sunnah.com

also referenced under: Book 1, Hadith 79 (English)