The sermon explores the concept of surety, contrasting worldly sureties with the ultimate surety of Christ, drawing heavily from Hebrews chapter 7 and Psalm 110. It examines Melchizedek as a figure foreshadowing Christ's role as a priest after the order of Melchizedek, emphasizing that Christ's surety is not merely a guarantee but a complete substitution, bearing the full weight of humanity's debt. The preacher highlights the security and assurance believers find in Christ's work, asserting that His surety provides a foundation for unwavering faith and hope, secured by God's oath and manifested through Christ's sacrifice and ongoing intercession.