v. 6. Even as Abraham believed God, and it was accounted to him for righteousness.
v. 7. Know ye, therefore, that they which are of faith, the same are the children of Abraham.
v. 8. And the scripture, foreseeing that God would justify the heathen through faith, preached before the Gospel unto Abraham, saying, In thee shall all nations be blessed.
v. 9. So, then, they which be of faith are blessed with faithful Abraham.
The apostle here reminds the Galatian Christians that were inclined to follow the Judaizing teachers of the example of Abraham, the ancestor of the Jewish nation, to whom the Jews were wont to refer with particular pride, and thus incidentally answers the questions of vv. 2 and 5. He quotes Gen_15:6 according to the Greek translation: Just as Abraham believed God, and it was counted to him for righteousness. See Rom_4:3. Not by any works which Abraham performed, but by his faith was he justified before God. For the faith of Abraham was not the mere assent to the words of the Lord upon that single occasion but it was faith in God as the Father of Jesus Christ and in the Messiah of the world, whose coming was promised to the patriarch. But Paul now draws a conclusion: You perceive, you understand, then, that they who are of faith, these are the children of Abraham. Since faith was the ground of Abraham's justification, it follows that all those that have the faith of Abraham are his true children. The mere bodily descent from Abraham secures salvation for no man, but as Abraham was saved, thus all believers are saved, namely, by faith. See Joh_8:39. No matter what the nationality of a person map be, if he proves himself a true child of Abraham by exhibiting the same faith in God and the Savior, then he will inherit the blessing given to Abraham and to his seed forever.
To this proof from Scriptures Paul adds another to show that the heathen were also included in the promise: Moreover, the Scripture, foreseeing that by faith God would justify the Gentiles, proclaimed the Gospel to Abraham before: Blessed shall be in thee all the nation; (or Gentiles). Paul's reference is to Gen_12:1-3; Gen_18:18, and he identifies the Word of God with the Scripture. God knew in advance that the Gentiles would be justified by faith: it was thus determined in His eternal and immutable counsels; He is the God that justifies by faith. Therefore the Gospel-message which was included in the promise to Abraham proclaimed a blessing to be bestowed upon all Gentiles. Since, however, the Gentiles were not connected with the Law of Moses, it is obvious that their justification could not be based upon anything else than their faith; works of the Law were excluded by the nature of the case. Therefore the conclusion offered by the apostle must be correct: So, then, they that are of faith are blessed with the believing Abraham. All men who, like Abraham, put their trust in their Lord and Savior in simple faith are included in the blessing of the promise. Men of faith are heirs of salvation, not men of works.