Galatians 3:6 “Consider Abraham: "He believed God, and it was credited to him as righteousness.”
Paul now begins to argue against the Judiazing heresy through theological and historical examples familiar to his audience and credible to those who valued a strong identity with the law and “Jewishness.”
“Consider Abraham” Paul’s reference is to one of the greatest pillars of the Jewish faith, and cites to Genesis 15:6 (which, as part of the Pentateuch, would be considered part of the “law of Moses,” and was in and of itself a well known proof text that Jews relied on to explain how Abraham was a model for how faith should work). Just as in Galatians 2:17, Paul ‘s presentation about salvation by faith is echoed in the book of Romans, where, in Chapter 4, Paul expands on this same verse in explaining the concept of "salvation by faith." (Its interesting – Galatians has been traditionally dated earlier than Romans – most scholars estimate by about 10 years – so it would seem that Galatians served, in part, as a “first draft” of many of the principles Paul expounds upon in the one book of the Bible (Romans) that probably encapsulates the life changing message of the Gospel more than any other).
Using Abraham as the prime example is important. Abraham was the model for all Pharisees, because Abraham served God from his heart, and not from obligation, which (despite indications to the contrary in the Gospels) was the essence of what the Pharisees tried to teach. Abraham destroyed idols, and stood up for God’s truth. But even more important, Abraham was a convert! He had lived as a gentile, and had accepted circumcision as his covenant sign after he committed his life to God. Abraham therefore was the model for all Gentiles who converted to Judaism – Abraham led many, many others to convert, accept the covenant of circumcision, and live under God’s law. Jewish tradition held that it was Abraham’s faithfulness to the covenant that led to the “credit” of righteousness, and some Jewish traditions went so far as to believe Abraham’s faithfulness was supernatural, and helped cover the sin of later generations. From the time of Abraham, there was always a hint of the concept of grace, or unmerited favor before God, but Jewish tradition always tied this to obedience in the covenant. But using Genesis 15:6 as his proof text, Paul will show here (and again, in Romans 4) that Abraham’s faith was the precursor of the Gospel, and the concept of “salvation” (in Genesis 15:6, "righteousness") for Abraham was fulfilled in the person of Jesus Christ.