How do we know that God's promises cannot be disannulled?

The Apostle Paul affirms that once God makes a promise, it cannot be disannulled or added to, similar to how a human testament is secure and unchanged. He emphasizes that the covenant made with Abraham was established in Christ before the law was given, indicating that the law, which came 430 years later, cannot invalidate this promise. This assurance rests in the character of God, who does not change and whose words are always fulfilled. God's promises to His people in Christ serve as a guarantee for their salvation, ensuring that all for whom Christ died will receive the promised blessings without the condition of their works or the law interfering.