(13) باب التَّسْلِيمِ وَالاِسْتِئْذَانِ 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. (ID)
Reference (ID): Sahih al-Bukhari 6244 (ID)
In-book reference (ID): Book 79, Hadith 18 (ID)
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 8, Book 74, Hadith 261 (ID)