Abu Wa'il said: Our master Ammar bin Yasir (may Allah be pleased with him) delivered to us a very brief and extremely eloquent sermon, so we said: O Abu Yaqzan! It would have been better if you had made this sermon longer. He said: I heard the Messenger of Allah (peace and blessings be upon him) say: "A man's prolonging of the prayer and shortening of the sermon is a sign of his understanding, so make the prayer long and the sermons short, and indeed some speech is (as) magic (in its effect)." (That is, some brief words have an effect like magic.)