3:6 righteousness. Paul here was referring to Genesis 15:6, as he also did in Romans 4:3, and as James did in James 2:23. Thus, as he repeatedly stresses, the doctrine of justification by faith in Christ, accompanied by the corollary truth of having Christ’s perfect righteousness imputed to us while He is made sin for us and bears our penalty, is not merely a divine afterthought following the failure of Israel under the law. It was the very means by which Abraham himself, the patriarchal father of Israel, was saved, and which continues to apply today.

3:7 children of Abraham. Abraham is not merely the ancestral father of the nation of Israel, but also of all those people of every nation and every age who come to the true God of creation (compare Genesis 15:5), through faith in His Son Jesus Christ (note John 8:56-58, concerning Abraham’s understanding of the coming day of Christ).

3:8 scripture. God’s original promise to Abraham, quoted here from Genesis 12:3, required the coming of Christ into the world to redeem the world for its fulfillment. Since the promise was with reference to “all nations,” and due to the fact that this was long before Israel became a nation, Abraham surely understood the promise to be of universal scope. Abraham thus believed this very early form of the gospel and was justified by faith many years before God gave him the sign of circumcision as a token of the covenant (Genesis 17:9-14).

3:8 justify the heathen. “Heathen” is the same as “nations” and “Gentiles.” God’s Word, as given to Abraham, therefore indicated that all nations would be justified by faith (at this time, there was as yet no distinction between Jews and Gentiles). This was a unique revelation in a day when all the world’s nations had already drifted away from monotheism and creationism and were relying on “works” to achieve whatever they may have understood by “salvation” or “justification.”