Paul quotes that Abraham “believed God, and it was counted to him as righteousness.” He concludes that those of faith are “sons of Abraham,” and that Scripture foresaw the nations being blessed in him (Galatians 3:6–9).
Paul appeals to Abraham to explain why non-Jewish believers can share in Abraham’s blessing. These verses sit inside Paul’s larger argument in Galatians 3 that the Galatians’ relationship with God should be understood from their beginning experience and from Scripture, not from adopting the law’s boundary markers.
Paul uses Abraham to make a controlled, Scripture-based argument about who shares in Abraham’s blessing. The text explicitly links Abraham’s right standing with God to believing God’s promise, and then draws a conclusion: people defined by faith are counted as Abraham’s “children” (verses 6–7).
A careful answer keeps the immediate passage, the book's argument, and the whole-Bible storyline together, so the question is answered in context instead of as a detached idea.
Start with Galatians 3:6-9, then read the surrounding section so the answer stays connected to the passage's flow.
6Even as Abraham "believed God, and it was counted to him for righteousness."
7Know therefore that those who are of faith, the same are sons of Abraham.
8The scripture, foreseeing that God would justify the Gentiles by faith, preached the gospel beforehand to Abraham, saying, "In you will all the nations be blessed."
9So then, those who are of faith are blessed with the faithful Abraham.