Sahih Al Bukhari 1: Chapter 3, Hadith 94

(94) Repeating one's talk thrice in order to make others understand

حَدَّثَنَا عَبْدَةُ، ‏‏‏‏‏‏قَالَ:‏‏‏‏ حَدَّثَنَا عَبْدُ الصَّمَدِ، ‏‏‏‏‏‏قَالَ:‏‏‏‏ حَدَّثَنَا عَبْدُ اللَّهِ بْنُ الْمُثَنَّى، ‏‏‏‏‏‏قَالَ:‏‏‏‏ حَدَّثَنَا ثُمَامَةُ بْنُ عَبْدِ اللَّهِ، ‏‏‏‏‏‏عَنْ أَنَسٍ، ‏‏‏‏‏‏عَنِ النَّبِيِّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ، ‏‏‏‏‏‏"أَنَّهُ كَانَ إِذَا سَلَّمَ سَلَّمَ ثَلَاثًا، ‏‏‏‏‏‏وَإِذَا تَكَلَّمَ بِكَلِمَةٍ أَعَادَهَا ثَلَاثًا".

SAHIH HADITH:

Narrated Anas: Whenever the Prophet asked permission to enter, he knocked the door thrice with greeting and whenever he spoke a sentence (said a thing) he used to repeat it thrice. (See Hadith No. 261, Vol. 8).

REFERENCE:

Sahih Al Bukhari 1: Chapter 3, Hadith 94