Both the apostle Paul and the leader of the church, James, use Abraham as examples when discussing salvation. This is interesting because Paul and James taught different gospels. This can be readily seen in how each author uses Abraham:

James:
Jas 2:20 But do you want to know, O foolish man, that faith without works is dead?
Jas 2:21 Was not Abraham our father justified by works when he offered Isaac his son on the altar?
Jas 2:22 Do you see that faith was working together with his works, and by works faith was made perfect?
Jas 2:23 And the Scripture was fulfilled which says, “ABRAHAM BELIEVED GOD, AND IT WAS ACCOUNTED TO HIM FOR RIGHTEOUSNESS.” And he was called the friend of God.
Jas 2:24 You see then that a man is justified by works, and not by faith only.

Paul:
Gal 3:5 Therefore He who supplies the Spirit to you and works miracles among you, does He do it by the works of the law, or by the hearing of faith?
Gal 3:6 just as Abraham “BELIEVED GOD, AND IT WAS ACCOUNTED TO HIM FOR RIGHTEOUSNESS.”
Gal 3:7 Therefore know that only those who are of faith are sons of Abraham.
Gal 3:8 And the Scripture, foreseeing that God would justify the Gentiles by faith, preached the gospel to Abraham beforehand, saying, “In you all the nations shall be blessed.”
Gal 3:9 So then those who are of faith are blessed with believing Abraham.
Gal 3:10 For as many as are of the works of the law are under the curse; for it is written, “CURSED IS EVERYONE WHO DOES NOT CONTINUE IN ALL THINGS WHICH ARE WRITTEN IN THE BOOK OF THE LAW, TO DO THEM.”
Gal 3:11 But that no one is justified by the law in the sight of God is evident, for “THE JUST SHALL LIVE BY FAITH.”

Those are both long quotes. To summarize:

James: Jas 2:24 You see then that a man is justified by works, and not by faith only.
Paul: Gal 2:16 knowing that a man is not justified by the works of the law but by faith in Jesus Christ,

Those who insist that Paul and James were preaching the same gospel create stories as to how both can be true at the same time. This can take multiple forms:

1. Works are the evidence of faith. Although works do not justify, they appear after justification.
2. Paul was talking about symbolic law. Paul believed that good works save (moral works), but Galatians is all about not performing the rituals that set Israel apart from the gentiles.
3. Works justify people to other people. Paul was talking about justification to God. James was talking about justification to men.

I have ranked these competing views by my subjective understanding of the popularity of each. Each view tries to reconcile how both authors can use Abraham while at the same time making very contrary statements. Although each view should be given due diligence, I believe all these views miss the mark.

The New Testament writers (and Jews in general) wrote in a fashion that marked trends in history. They used the Old Testament to show precedence. How those events were marked held remarkable latitude. I have written previously about Matthew’s loose usage of Old Testament texts.

Paul can likewise be seen using Old Testament examples very liberally:

Rom 9:25 As He says also in Hosea: “I WILL CALL THEM MY PEOPLE, WHO WERE NOT MY PEOPLE, AND HER BELOVED, WHO WAS NOT BELOVED.”

Here Paul is saying that God is accepting the gentiles. The gentiles were once not God’s people, but now they are. As a proof text he quotes Hosea 2:23. But the thing is that Hosea is not at all talking about the gentiles. The prophecy concerns a remnant of Israel which is faithful. Hosea 1 and 2 talks about how Israel will return to God in the future. Paul, here, makes the opposite point that the text makes. Paul says that God is grafting in gentiles!

But this type of proof texting was common at the time of Paul. The point in quoting the Old Testament was not to show predictions, but to show parallels. Sometimes the text had to be stretched a little.

In this way, both Paul and James can use Abraham as examples of justification. They both had different points, but there was enough precedence that they could make competing points.

The most striking thing is that both James and Paul, if taking about justification to salvation, are both using Abraham’s justification out of context. Abraham did not go to heaven or was not slated to enter the Kingdom of God. Abraham went to Abraham’s Bosom (paradise) when he died.