Paul strongly exhorts the "foolish Galatians" because they were allowing the Judaizers to persuade them to trade the priceless freedom that Christ earned for them by His death on the cross for bondage to the Law! That is a foolish trade-off. Why would they, who were saved by grace, want to go back to the Law?
The Judaizers looked to Moses as the purveyor of the Law, but Paul went all the way back to Abraham in Genesis 15:6. Abraham was justified (declared righteous) by God on the basis of faith and not works, having been justified before the Law was even instituted. Justification has always been by faith.
Even though Abraham is considered the father of Judaism and revered by Jews, he was a Gentile, from a pagan Chaldean background; but his faith saved him because he "believed God, and it was reckoned (credited) to Him as righteousness" (Genesis 15:6).
Praise God that "Christ redeemed us from the curse of the Law having become a curse for us" (Galatians 3:13)!
Here are important cross-references from Genesis that give background to Galatians 3. I have included inductive study questions to help you dig a little deeper:
Genesis 12:1-9 - What did God say to Abram? What did Abram do?
Genesis 15-17 - This is the setting for Romans 4:3, 9, 22 and Galatians 3.
Genesis 15:6 – This is a key verse to memorize. How are we justified?PRAYER
We are so grateful that there is nothing that we can do to earn our justification. Thank You Jesus for becoming a curse for us so that we might be redeemed! Amen.