Repeating words three times
Anas (radi Allahu anhu) reported: “Whenever the Prophet (sal Allahu alaihi wa sallam) said something, He would repeat his words thrice (i.e. three times) so that the meanings would be understood fully.”
[Sahih Al-Bukhari and Muslim]
To stress a point thrice (i.e. three times) is sometimes required and preferable. It is particularly so when a situation demands and when explaining a point to the audience once or twice may not be enough. It is useful when you are mentioning an important point to repeat it three times so as to stress the importance of this point to the audience.
And Allah knows best!