This is a great question, and it lies at the very crux of the Protestant Reformation! Are we saved by faith in Christ alone, or does our subsequent obedience also form part of the basis for our salvation? The Protestant church generally holds to the first view, and the Catholic faith to the second.*
There are two Bible verses in particular which have caused the question to be debated for many centuries. First, in Romans 3:28 Paul lays down the gospel message in its powerful simplicity: For we maintain that a man is JUSTIFIED by faith apart from observing the law. Or apart from works of the Law (NASB). That sounds like wonderful and liberating news, but it appears to be quickly contradicted by James. Here’s his observation: You see that a person is JUSTIFIED by what he does and not by faith alone (2:24). And he refers back to a callous man, a supposed Christian, who says casually to a destitute person: “Go, I wish you well; keep warm and well fed,” but does nothing about his physical need.
The key to this apparent dilemma is to realize that the Bible writers comprehended two distinct meanings for this word “justified” (in Greek, dikaioō). The paramount meaning is that of “being declared righteous.” When you and I are judged, and God declares us righteous, or states before the universe that we are eligible to receive a heavenly home, on what basis does he do that? What is the legal justification for our salvation? It is the cross of Jesus Christ! We are justified, not on the basis of our obedience or our innate self-worth, but because God sent his son to die for our sins.
Paul affirms this idea again in Romans 5:1 where he writes, Therefore, since we have been justified through faith, we have peace with God through our Lord Jesus Christ. Again, this speaks to the cause of our salvation, or the root of our newfound peace with God – through Jesus’ death on the cross.
But a second meaning exists for the word justified: and that is to prove right, or to demonstrate validity. I make a certain decision, and later events justify or prove that decision correct. Imagine a CEO of a firm who announces to his workers: “We’re going to implement this new plan. In coming weeks, I think you’ll see that it improves morale and boosts our profits.” Sure enough, six months later everyone agrees that his action was justified. So the loving, obedient deeds we do as Christians are not a basis for salvation, but they do demonstrate or justify the reality that something has happened within our hearts because of Jesus’ gift of salvation.
Interestingly, even Jesus borrows this second meaning in Luke 7, when faced with criticism. He reminded the religious rulers that they had condemned the austere John the Baptist for his somber message of repentance. “He has a demon,” they said. When Jesus, in contrast, dined and fellowshipped with sinners, they called him a winebibber! But Jesus made the point that a prophet’s “fruits” would prove that his message was worthy. Notice how he says it in the King James Version: But wisdom is JUSTIFIED of all her children. In the NIV, we read it this way: But wisdom is PROVED RIGHT by all her children.
So both Paul and James agree that the firm foundation of our salvation is the cross. They further agree that healthy, vibrant faith will always be demonstrated in loving acts (Matthew 25) and an obedient life (John 14:15).
Thanks to John Ankerberg and John Weldon for material from their book, Protestants & Catholics: Do They Now Agree?