'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. (Using translation from Muslim 869)
خَطَبَنَا عَمَّارٌ ؓ فَأَبْلَغَ وَأَوْجَزَ فَلَمَّا نَزَلَ قُلْنَا يَا أَبَا الْيَقْظَانِ لَقَدْ أَبَلَغْتَ وَأَوْجَزْتَ فَلَوْ كُنْتَ تَنَفَّسْتَ؟ فَقَالَ سَمِعْتُ رَسُولَ اللهِ ﷺ يَقُولُ إِنَّ طُولَ صَلَاةِ الرَّجُلِ وَقِصَرَ خُطْبَتِهِ مَئِنَّةٌ مِنْ فَقْهِهِ فَأَطِيلُوا الصَّلَاةَ وَأَقْصِرُوا الْخُطَبَ وَإِنَّ مِنَ الْبَيَانِ لَسِحْرًا