Pastor Tyler Wittmer's sermon focuses on Christ's return as sudden and believers' need to be prepared. He emphasizes the importance of holding onto orthodox beliefs and understanding theological triage to maintain unity in the Church. The congregation is encouraged to prioritize essential doctrines, anticipate Christ's return, and support one another in the truth of the gospel and hope of salvation. The sermon ends with communion as a reminder of Christ's sacrifice and the assurance of salvation through Him.