Sahih Muslim 2009
صحيح مسلم#2009SahihAbu Wa'il reported:'Ammar delivered to us the sermon. It was short and eloquent. When he (, Ammir) descended (from the pulpit) we said to him: 0 Abd al-Yaqzn, you have delivered a short and eloquent sermon. Would that you had lengthened (the sermon). He said: I have heard the Messenger of Allah (ﷺ) as saying: The lengthening of prayer by a man and the shortness of the sermon is the sign of his understanding (of faith). So lengthen the prayer and shorten the sermon, for there is charm (in precise) expression
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Every narration in Sahih Muslim is accepted as Sahih (authentic) by the established status of the book.
In-book reference: 7:59