Some points discussed during this Khutbah:

Virtues and obligation of understanding the meaning of Lā ilāha illa Allāh.
The purpose of sending the Prophets and Messengers.
Responding to those who claim all of the ummah says Lā ilāha illa Allāh so there is no need to call to Tawḥid.
Examples of violations of Tawḥeed that have crept into the ummah.
The importance of learning Tawḥeed and what violates it.
Proof that entering into Islam (Tawḥid) wipes away everything that came before it, even trying to kill a Prophet of Allah.