Sahih al-Bukhari 6244
صحيح البخاري#6244Sahihحَدَّثَنَا إِسْحَاقُ، أَخْبَرَنَا عَبْدُ الصَّمَدِ، حَدَّثَنَا عَبْدُ اللَّهِ بْنُ الْمُثَنَّى، حَدَّثَنَا ثُمَامَةُ بْنُ عَبْدِ اللَّهِ، عَنْ أَنَسٍ ـ رضى الله عنه أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم كَانَ إِذَا سَلَّمَ سَلَّمَ ثَلاَثًا، وَإِذَا تَكَلَّمَ بِكَلِمَةٍ أَعَادَهَا ثَلاَثًا.
Narrated Anas:Whenever Allah's Messenger (ﷺ) greeted somebody, he used to greet him three times, and if he spoke a sentence, he used to repeat it thrice
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 al-Bukhari is accepted as Sahih (authentic) by the established status of the book.
In-book reference: 79:18