In "The Guarantee of Glory," Gilbert Barr explores the assurance of salvation, emphasizing the idea that those chosen by God are eternally secure in their relationship with Him. He draws from Philippians 1:3-6, where Paul expresses his confidence that God, who began a good work in believers, will see it to completion. Barr likens this to the believers' unbreakable bond with God, highlighting that once someone is truly saved, they cannot lose their salvation.

He underscores this point by addressing common misconceptions and arguments against eternal security. Barr references various scriptures, including John 6:39, Romans 8:29-30, and 1 John 2:19, to support his argument that true believers will endure to the end and that any apparent fall from faith indicates that a person was never genuinely saved to begin with.

Barr also reflects on the deceitfulness of appearances, using Judas Iscariot as an example. Despite Judas' outward actions, he was never truly a believer, which is evident by his ultimate betrayal of Jesus. This distinction between outward appearances and genuine faith is crucial in understanding the perseverance of true believers.

Moreover, Barr provides encouragement to believers, emphasizing that their endurance and perseverance are evidence of God's work within them. He quotes Job 17:9 and other scriptures to illustrate that the righteous will grow stronger in their faith over time. He also reassures that nothing, including tribulation, distress, or persecution, can separate believers from the love of God.

Barr concludes by reminding believers of their victory in Christ, encouraging them to remain steadfast and unmovable in their faith. He emphasizes that their labor for the Lord is never in vain, reinforcing the eternal security and ultimate glory promised to those who truly belong to God. This sermon serves as a powerful reminder of the unwavering faithfulness of God and the assurance of salvation for all true believers.