General Behavior (Kitab Al-Adab)
Dawud :: Book 41 : Hadith 4990
Narrated Amr ibn al-'As:
One day when a man got up and spoke at length Amr ibn al-'As said If he had been moderate in what he said: It would have been better for him. I heard the Apostle of Allah (peace_be_upon_him) say: I think (or, I have been commanded) that I should be brief in what I say, for brevity is better.