How do we know the covenant of grace is truly everlasting?

The assurance of the everlasting nature of the covenant of grace is based on God's faithfulness and the sacrificial death of Jesus Christ. Hebrews 13:20 refers to the blood of the everlasting covenant, highlighting that this covenant is not contingent on human actions but on Christ's fulfilled work. Furthermore, God's promises are immutable, meaning they cannot change or fail. Therefore, those in Christ can have confidence in their eternal union with Him, inheriting the spiritual blessings that were promised to Abraham and fulfilled through Him.