Galatians 3
Abraham's Faith Counted as Righteousness — Romans 4
Paul proves justification by faith from the Old Testament itself, citing Gen 15:6: "Abraham believed God, and it was counted to him as righteousness." He develops this throughout Rom 4:1-12, arguing that the reckoning came before circumcision, so Abraham is father of believing Jew and Gentile alike. What does this "counting" mean? Wright stresses covenantal-membership language; the Reformers read the imputation of a righteousness received as gift; Trent emphasized that the same grace truly renews the believer. The contrast in 4:4-5 between wages and gift is what all affirm: righteousness is reckoned "to the one who does not work but believes." This Abrahamic promise anchors the covenant of grace traced through Gen 17:7 and reappears in Gal 3:6. Augustine had already insisted that even faith is God's gift, lest grace be owed, a point the Council of Orange made the church's common teaching.
The Abrahamic Covenant — Genesis 15 and 17
Gen 15:5-6 records the covenant promise and Abraham's response: he "believed the LORD, and he counted it to him as righteousness." In Genesis 15 God alone passes between the pieces, binding himself by oath. Calvin made the Abrahamic covenant the template of the one covenant of grace, and Augustine read the promise as fulfilled in Christ and the church. The sign of circumcision in Gen 17:7-11 seals the promise to Abraham and his offspring. Paul makes Genesis 15:6 the proof text of justification by faith in Rom 4:3 and Gal 3:6. The covenant with Abraham reaches forward to embrace the Gentiles in Christ.