Why is understanding God's immutable covenant important for Christians?

The immutability of God's covenant is central to the believer's assurance in their salvation. As the sermon emphasizes, God's promises are irrevocable and grounded in His eternal will, as seen in Galatians 3:15, which asserts that once a covenant is confirmed, no one can annul or add to it. This assurance helps believers navigate life's uncertainties, knowing that their salvation rests not on their fluctuating obedience, but on the unchanging nature of God’s covenant made with Christ. It's a comforting truth that empowers Christians to live by faith, fully trusting in God's promises.