How do we know God's promises are true in relation to the law?

In Galatians 3:17-18, Paul emphasizes that the covenant of promise, which was given to Abraham, remains unchanged despite the introduction of the law. The law, which came 430 years later, does not disannul the promise; instead, it complements it by highlighting our inability to achieve righteousness through our own efforts. God's promises are thus upheld by His faithfulness, ultimately realized through Christ, who fulfills both the law and the promise. The faithfulness of Christ reveals the depth of God's grace, ensuring that we are justified by faith rather than by the law.