Wa `alaykum as-Salamu wa Rahmatullahi wa Barakatuh.
In the Name of Allah, Most Gracious, Most Merciful.
All praise and thanks are due to Allah, and peace and blessings be upon His Messenger.
Brother, first of all, we’d like to say that we are impressed by your question, which emanates from a thoughtful heart. May Allah Almighty help us all adhere to the principles of this true religion, Islam, and enable us to be among the dwellers of Paradise in the Hereafter, amen.
In fact, the purpose of Friday khutbah (sermon) is to remind the Muslims about their responsibilities and to motivate them to stop evil and promote good in their lives, families and in the community. It is also the purpose of the Friday khutbah to inform the Muslims about the condition of the Ummah and the world.
Dealing with the question in point, the European council for Fatwa and Research issues the following Fatwa:
The Friday sermon is a reminder, a call, a guidance and a means of education. We learn that whenever Allah’s Messenger (peace and blessings be upon him) delivered the sermon, his eyes would become red, his voice rose, with intense emotion as one giving a warning against the enemy.
Such a spellbinding way of delivering sermon related to the fact that the overwhelming motive was to remind the Muslims. Hence, it is narrated that he used to read Surat Qaf in the Friday prayer, which by itself, is a reminder and a warning.
However, it should be borne in mind that the Prophet (peace and blessings be upon him) used not to prolong the sermon so as not to bore the listeners. He is also reported to have said, “Shortening the sermon and prolonging the prayer is a sign of the man’s knowledge.” (Muslim)
Allah Almighty knows best.