How do we know the doctrine of God's covenant is true?

God's covenant is true because it is rooted in His immutable character and the historical realization of His promises. As noted in passages like Psalm 89:34, God declares, 'My covenant will I not break, nor alter the thing that is gone out of my lips.' This consistency assures believers that God will fulfill His covenant. The ultimate testament to its truth is found in Christ Jesus, who fulfilled all righteousness and secured the blessings of the covenant for His chosen people. Therefore, the covenant's certainty lies in God's unwavering commitment to His children, confirmed by the work of Christ.