John Gill emphasizes that the Lord is not slow in fulfilling His promises, particularly regarding the second coming of Christ. He explains that the perceived delay is due to God's longsuffering, allowing time for the elect to come to faith and repentance. Gill clarifies that God's patience is not for everyone but specifically for His chosen ones, ensuring that none of them perish. He reassures believers that God's promises are certain and that His timing is perfect, ultimately leading to the salvation of His people. The sermon encourages trust in God's plan and His desire for all to come to repentance.