What is the most important Christian doctrine? That sounds like something ivory tower scholars debate in the dusty confines of a seminary apart from everyday life. But the apostle Paul didn’t think that was a bad question; he spent two books of the Bible on this central topic for which he was willing to die. The word “doctrine” simply means a topic of great importance for the faith. You don’t want to be wrong about it! Historically, one topic divided the church back in the 1500s and resulted in what has come to be called Protestantism. It continues to delineate true believers from false, those who live by faith and those who live by works. Even though both can look like “Christians” on the outside, their beliefs about this subject are polar opposites.

The doctrine is “Justification,” that is, how to become righteous and acceptable to God. The teaching about what justification is and how it should make a difference in our lives is particularly taught in the books of Romans and Galatians. In the first of these, the apostle spends the initial eleven chapters laying it out like a doctoral thesis. This is not reading material for the lazy-minded who want an inspiring verse here or there. No, it is for those who want to go deeper in understanding this great truth—because it is so important to understand, yet it trips up so many. The rest of the book of Romans (the final five chapters) begins with the segue, “Therefore,” and deals with applying the truth of justification to our everyday life. In other words, if all Paul wrote in the book’s first part is true, how shall we live in light of that truth?

The book of Galatians, also authored by the apostle Paul, is compressed into a short form, only six chapters. He teaches the truth of justification by faith by contrasting it with justification by works. Here, Paul plants his flag; it’s the hill on which he stands. He is willing to go to the wall on this truth. We better get this right! Listen to the intensity of what he wrote to the Galatians:

But even if we, or an angel from heaven, should preach to you a gospel contrary to what we have preached to you, he is to be accursed! As we have said before, so I say again now, if any man is preaching to you a gospel contrary to what you received, he is to be accursed! (Gal. 1:8–9)

But here is the rub, the tiny word “by.” What does it mean to be justified “by” faith? There are times when the Bible does, in fact, say other things besides faith justify us. What gives? It all depends upon what we mean by the word “by.” The English term, like all prepositions, is challenging to nail down. Consider the following examples:

The ball was hit by the boy.
The ball landed by the fence.
It began to rain by the time the boy found the ball.
He hit it far by swinging hard.
By golly, that was a good hit.

In each example, the term “by” means something different. This phenomenon is also true for prepositions in the Greek language of the New Testament. The various English translations of the Bible wrestle with this, resulting in differing versions for the same Greek grammatical constructions from the original language.

At the risk of oversimplifying this, we present a chart* below showing the various factors involved in how we obtain justification, that is, how we can understand the different shades of what it means to be justified and by what we are justified. None contradict the others, but they present a holistic, integrated understanding of Justification.