What does Romans 3:28 mean?

This verse is a summary of what Paul has written in Romans 3:21–27. It also serves as a useful, concise proof that our salvation is not, in any sense, dependent on good deeds, rituals, sacraments, or other behaviors. Prior verses made it clear: we cannot and will not be seen as righteous before God on the basis of our own efforts (Romans 3:10). However, unless God declares a person to be "justified"—righteous, having no sin in need of punishment—that person cannot be with God. The unjustified person has earned God's angry judgment.

Paul has shown that nobody is able to reach this level of being justified by following the works of the law. Human beings can't do it. We sin. It's in our nature. Once we have sinned, the price of our sin is to be excluded from God's glory (Romans 3:23).

Thankfully, God provides a way—but only one way—for humans to be declared "justified." This comes through faith and not through works of the law. Later, Paul will expand on this to further prove that this salvation is entirely on the basis of faith, with no contribution or requirement of works, whatsoever (Romans 4:3; 11:6).