Still More on God's Promises and God's Law
The Lord desires that we should have great certainty concerning His promises. Our God does not want us to be plagued with apprehension concerning the fulfillment of His promises. In all that God has promised, He intends for us to stand in bedrock assurance: "that the promise might be sure to all the seed." This certainty is based upon two sets of related truths: one between His promises and His grace, and another between His grace and faith in Him.
The first set of related truths mentioned here (that makes God's promises sure) is His promises and His grace. Living by God's promises allows us to walk in the all-sufficient grace of God. The heavenly dynamic behind the promises of God is the grace of God. If God's promises are to be sure in our lives, we must relate to them "according to grace." If we are counting on any other hope besides grace to make God's promises certain, we will never stand in full assurance of the promises being fulfilled. If God's promises depend upon our performance, we will never walk in full assurance. If His promises depend upon the faithfulness or ability of others, full assurance will always elude us. The fulfillment of God's promises depends wholly on His grace.
Now, how do we treat God's promises in a way that does not disregard the grace that is behind them? The only acceptable response is faith. "Therefore it is of faith that it might be according to grace." Every other response creates a discord with grace. This was the great mistake that Abraham and Sarah made early in their pilgrimage with the Lord. When they relied upon their own ingenuity (using the slave girl, Hagar, to try to supply the son God had promised), they were operating outside the realm of dependence upon God. Basically, they were trusting in themselves.
Behind all of the promises of the gospel is the promised Savior, who would die on the cross for our sins. If we attempt to base God's saving work on our performance, we are setting aside God's grace. We are inferring that His death for us was unnecessary or inadequate. "I do not set aside the grace of God; for if righteousness comes through the law, then Christ died in vain" (Galatians 2:21).