Abu Malik al-Ashja'i narrates from his father: "We used to sit with the Messenger of Allah (peace and blessings be upon him) while we were young boys, and I never saw a man who remained silent longer than the Messenger of Allah (peace and blessings be upon him). And when his Companions talked and began to talk a great deal, he (peace and blessings be upon him) would smile."
Hadith Referenceالمعجم الكبير للطبراني / باب الطاء / 8167