Do works save you, or do works reveal that you are saved?

Both are true. We are not saved by faith alone; if that were true there would be a statement in the Bible saying you are saved by faith alone without any works, but there is no such statement. Romans 3:28 says we are saved by faith without works of the law, because your first movement to God is by faith, not by works. It is like meeting a friend: you begin the relationship by exchanging who you are, on faith, not by walking up and showing off your talents. That is why God rejected the Jews coming to him on the basis of works, as in Romans 4, thinking that because they were sons of Abraham, God owed them. Abraham did not come to God by works; he believed God, and that is how the relationship started. But then the relationship has to mature, and that is why the New Testament requires works: faith gets you to know one another, but works carry the relationship and give it a strong foundation. So works are not how you begin, that would be putting God on the spot to owe you, but they are how the faith you began with grows. Keeping those two kinds of works distinct is the hard part of theology.