Our Protestant brethren say that one is justified by faith once for all and not at all by works.

Catholics say that initial justification is “monergistic” (not involving our work to attain it) and by faith only, but ongoing justification is by faith and works. And justification can be lost if one rejects God or spurns his grace.

In Genesis 12 Abraham was justified by faith and works together. God told him to leave his home and trust him for the future, and he did so (a work): “So Abram went, as the LORD had told him” (12:4). Then he built two altars to the Lord (good works again) in 12:7-8. These were good works of obedience, and as a result, God blessed him greatly and said to him, “I will make of you a great nation, and I will bless you, and make your name great ... by you, all the families of the earth shall bless themselves” (12:2-3).

Faith is never mentioned in the chapter, but Abraham clearly exercised it when he obeyed God’s instructions. If the point of the narrative was actually to highlight faith as opposed to works, it seems odd that Abraham’s work is mentioned and commended, but not his faith. The book of Hebrews interprets Genesis 12, stating that “By faith Abraham obeyed when he was called to go out to a place which he was to receive as an inheritance; and he went out, not knowing where he was to go” (11:8), and “by faith he sojourned in the land of promise ...” (11:9). Therefore, this instance of justification was by faith and works. Abraham had the faith to believe God (faith), and he obeyed him (a work).

Hebrews 11 is about the heroes of the faith. Faith is described as leading to men receiving God’s “divine approval” (11:2), which sounds very much like justification. Abel “received approval as righteous” (11:4). Enoch is described as “having pleased God” (11:5). If it’s denied that Genesis 12 is a justification, then it has to be explained how Hebrews 11:8 describes the passage as Abraham exercising faith. This must be justification in the Protestant sense because fallen man on his own cannot have or exercise true faith: “And he believed the LORD, and he reckoned it to him as righteousness (Genesis 15:6).”

In Genesis 15:6, Abraham was justified as a result of having “believed the Lord.” In Romans 4, St. Paul offers an extensive interpretation and emphasizes faith, over against the Jewish works of circumcision as a supposed means of faith and justification (hence, he mentions circumcision in 4:9-12, and salvation to the Gentiles as well as Jews in 4:13-18). James (2:23) gives an explicit interpretation of the Old Testament passage, by stating, “And the scripture was fulfilled which says, ‘Abraham believed God, and it was reckoned to him as righteousness,’ and he was called the friend of God.” The previous three verses were all about justification, faith and works, all tied in together (2:20: “faith apart from works is barren”; 2:22: “faith was active along with his works, and faith was completed by works”) and this is what James says “fulfilled” Genesis 15:6. James 2:24 then condemns the Protestant notion of “faith alone” in the clearest way imaginable: “A man is justified by works and not by faith alone.”

James 2 is usually thought by Protestants to refer to sanctification, yet it only mentions the word “justified” (dikaioo) three times (2:21, 24-25): the same Greek word used in Romans 4:2, as well as 2:13; 3:20, 24, 28; 5:1, 9; 8:30; 1 Corinthians 6:11; Galatians 2:16-17; 3:11, 24; 5:4; and Titus 3:7. If James actually meant sanctification, he could have used one of two Greek words (hagiazo / hagiasmos) for that concept.

Genesis 22, the passage about Abraham being willing to sacrifice his son Isaac if God commanded him to do so, provides a third example where Abraham is said to be “justified.” God spoke through the angel of the LORD and said, “Because you have done this ... I will indeed bless you, and I will multiply your descendants ... because you have obeyed my voice” (Genesis 22:16-18). Genesis 22 already establishes that it was a work of Abraham that brought about God’s renewed covenant with him. Just as Paul does with regard to Genesis 15:6, so does James offer an authoritative, detailed, developed interpretation of the events recorded in Genesis 22: “Was not Abraham our father justified by works, when he offered his son Isaac upon the altar?” (2:21). The book of Hebrews adds: “By faith Abraham ... offered up Isaac” (11:17).

Works are always present where true faith exists. James doesn’t deny that Abraham also had faith, which was part of his justification as well (2:18, 20, 22-24, 26). But God had already reiterated in Genesis itself that works were central to Abraham’s justification (and anyone’s) — without faith or belief being mentioned (Genesis 18:19):

I have chosen him, that he may charge his children and his household after him to keep the way of the LORD by doing righteousness and justice; so that the LORD may bring to Abraham what he has promised him.

It’s interesting that Genesis never mentions the “faith” of Abraham (at least not by using that word), even though he is considered the exemplar and “father” of monotheistic faith. But it does mention plenty of his works. Nor does the entire Protestant Old Testament do so. But the Catholic Deuterocanon refers to his great faith (1 Maccabees 2:52; 2 Maccabees 1:2), which. is predominantly highlighted in the New Testament (Romans 4; Galatians 3; Hebrews 11; James 2), while not ignoring the fact that works also played a key role in Abraham’s justification. Moreover, Scripture asserts that Phinehas (Numbers 25:11-13) and Rahab (James 2:25) were justified by works.