How do we know the doctrine of eternal inheritance is true?

The doctrine of eternal inheritance is validated through numerous passages that demonstrate God's unchanging promise to His people. In Hebrews 6:17-18, God willing to show more abundantly to the heirs of promise the immutability of His counsel, confirmed it by an oath. This underscores the security and certainty of the inheritance promised to believers. Furthermore, the saints’ eternal inheritance is part of the New Covenant, securing their claim over everything that belongs to God. The assurance of this inheritance comes not merely from abstract theological concepts but directly from the faithfulness of God, who cannot lie and who binds Himself to His promises for the sake of His elect.