The sermon discusses the role of Aaron and his descendants in making atonement for Israel through offerings, contrasting this with the permanent priesthood of Jesus Christ, who made atonement for his elect once and for all. It emphasizes gratitude for Christ's sacrifice, ensuring eternal redemption for believers, and highlights the significance of names written in the Book of Life. The sermon concludes with a call to confess sins and trust in God's grace for salvation, urging believers to share the good news of Jesus' death and resurrection.