696. anas (may allah be pleased with him) reported: whenever the prophet (pbuh) said something, he would repeat his words thrice so that the meanings would be understood fully; and whenever he came upon a group of people, he would greet them, and he would repeat salutation thrice.
[al-bukhari and muslim].

commentary:  to lay stress on a point thrice or to repeat greetings, according to this hadith, is preferable. it is particularly so when a situation so demands and when explaining a point to the audience once and twice may not be enough.

697. `aishah (may allah be pleased with her) reported: the speech of messenger of allah (pbuh) was so clear that all those who listened to it would understand it.
[abu dawud].

commentary:  interpreting `aishah's report, some commentators say that messenger of allah (pbuh) used to speak clearly and decisively. however, it may also mean that, while speaking, he would pause upon his words in such a way that each and every word which came from his lips appeared detached from the other. he was never like those who speak quickly and their words are mixed up with each other. this hadith reflects the prophet's eloquence as well as his due care and decency in putting in his viewpoint to the convenience of his audience.