For the promise, that he should be the heir of the world, was not to Abraham, or to his seed, through the law, but through the righteousness of faith…Therefore it is of faith, that it might be by grace; to the end the promise might be sure to all the seed – Romans 4:13,16
“When the righteous turns from his righteousness and commits iniquity, he shall even die thereby.” But see the excellence of salvation by Grace—when you reach the ground of faith in the promises, you are upon terra firma and your soul is no longer in jeopardy. Here is a sure foundation, for the Divine promise cannot fail! If my salvation depends upon the Lord and is received by me on the ground that the Lord has decreed it, promised it in Covenant and ensured it to me by the blood of Jesus Christ, then it is so mine that neither life nor death nor Satan nor the world shall ever rob me of it! If I live to the age of Methuselah, my faith will have the same promises to rest upon—and clinging there she will defy the lapse of years to change her immutable security.
The promise would not be sure to one of the seed by any other means than that of Grace through faith, but now it is sure to all the seed. Moreover, if the promise had been made to works, there are some of the seed to whom, most evidently, it never could come. One of the seed of Abraham hung dying upon a cross and within an hour or two his bones were broken that he might the more quickly die. Now, if salvation to that poor dying thief must come by works, how can he be saved? His hands and feet are fastened up, and he is in the very grip of Death—what can he do? The promise would not have been sure to him, my Brothers and Sisters, if there had been any active condition! But he believed, cast a saving eye upon the Lord Jesus and said, “Lord, remember me,” and the promise was most sure to him, for the answer was, “Today shall you be with Me in Paradise”!