Bismillah Walhamdulillah Was Salaatu Was Salaam ‘ala Rasulillah
Narrated Anas (Radi-Allahu ‘anhu):
Whenever Allah’s Apostle (Sallallahu ‘Alaihi Wa Sallam) greeted
somebody, he used to greet him three times, and if he spoke a sentence,
he used to repeat it thrice.
Bukhari Vol. 8 : No. 261