‘Ammar told how he heard God’s Messenger say, “The length of a man’s prayer and the shortness of his sermon are a sign of his understanding, so make the prayer long and the sermon short, for there is magic in eloquence.”
Jabir b. Samura said the Prophet gave two sermons between which he sat, recited the Qur’an and gave the people an exhortation and both his prayer and his sermon were of moderate length.
Jabir said that when God’s Messenger preached his eyes became red, his voice rose and his anger became violent, so that he was like one warning an army and saying, “The enemy has made a morning attack on you.” “The enemy has made an evening attack on you.” He would Say, “The last hour and I have been sent like these two,” and he would join his forefinger and his middle finger.
As-Sa’ib b. Yazid said that in the time of God’s Messenger, Abu Bakr and ‘Umar the beginning of the summons on Friday was when the imam took his seat on the pupilt, but in 'Uthman’s time when (the people were numerous he added the third call on az-Zaura’.*