Whenever the Prophet ﷺ 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).

عَنِ النَّبِيِّ ﷺ أَنَّهُ كَانَ إِذَا سَلَّمَ سَلَّمَ ثَلاَثًا وَإِذَا تَكَلَّمَ بِكَلِمَةٍ أَعَادَهَا ثَلاَثًا

Whenever Messenger of Allah ﷺ greeted somebody, he used to greet him three times, and if he spoke a sentence, he used to repeat it thrice.

أَنَّ رَسُولَ اللَّهِ ﷺ كَانَ إِذَا سَلَّمَ سَلَّمَ ثَلاَثًا وَإِذَا تَكَلَّمَ بِكَلِمَةٍ أَعَادَهَا ثَلاَثًا

"When the Messenger of Allah ﷺ would give the Salam he would do so three times, and when he would say a statement, he would say it three times."

أَنَّ رَسُولَ اللَّهِ ﷺ كَانَ إِذَا سَلَّمَ سَلَّمَ ثَلاَثًا وَإِذَا تَكَلَّمَ بِكَلِمَةٍ أَعَادَهَا ثَلاَثًا

"When the Messenger of Allah ﷺ would give the Salam he would do so three times, and when he would say a statement, he would say it three times." (Using translation from Tirmidhī 2723)

«أَنَّ رَسُولَ اللَّهِ ﷺ كَانَ إِذَا تَكَلَّمَ بِكَلِمَةٍ أَعَادَهَا ثَلَاثًا لِتُعْقَلَ عَنْهُ»

[AI] The translation of the passage in English is: "That the Messenger of Allah ﷺ used to speak three times so that his statement would be understood."

«أَنَّ رَسُولَ اللهِ ﷺ كَانَ إِذَا تَكَلَّمَ تَكَلَّمَ ثَلَاثًا لِكَيْ يُفْهَمَ عَنْهُ»