How do we know the doctrine of the covenant of grace is true?

The doctrine of the covenant of grace is established through various scriptures that demonstrate God's unchanging commitment to His elect. For instance, in Ephesians 1:4-5, Paul affirms that we were chosen in Christ before the foundation of the world and that through Christ, God has predetermined to adopt us as His children. This reflects the inseparable link between God's purpose and grace. The entire narrative of Scripture reveals the continuity of God's covenant: from the promises to Abraham through to the fulfillment in Christ, which assures us of the immutable nature of God's decrees, thus validating the doctrine of the covenant of grace.