Salvation by Works means that one is saved by the merits of one’s own works. The teaching is heresy because the Bible says that we are condemned by our works and cannot be saved by them. The Bible says we are saved by believing in Jesus. But there is quite a bit of hypocrisy going on in the Church as to what constitutes someone teaching a salvation-by-works “gospel”.
Regardless of which Church you go to, there are a set of rules that the Church expects you to follow or they’ll say that you’re not a real Christian. They also say that only Christians are saved. Therefore, what they are teaching is compliance with a set of rules or you are definitely not saved. These rules that they say you have to follow if you want to be saved are claimed to be at the back of the Book.
The opposition to this states that the rules that need to be followed are at the front of the Book. Both claim that you can only be saved by faith in Jesus. But one side teaches obedience to the commandments at the front of the Book while the other side teaches obedience to (some of) the commandments at the back of the Book. Both sides teach that if you refuse to follow these commandments, then you have no salvation. And both sides claim that they do not teach the salvation-by-works heresy.
So where’s the hypocrisy? The Church states that if you teach obedience to the commandments at the front of the Book, then you are, by definition, teaching salvation by works. Both sides teach that you cannot be saved if you don’t follow the rules, but the Church claims that their opposition teaches salvation by works because the rules that need to be followed are at the front of the Book. The issue is not about whether you need to follow the rules, but which rules you say you have to follow in order to not be teaching salvation by works.
If we were to consistently apply the logic that needing to follow rules equates to salvation by works, then everyone who teaches that there are any rules to follow is guilty of teaching this heresy. In order to be logically consistent with the claim and not be guilty of what they say their opposition is guilty of, then the Church would need to teach that there are no rules to follow, at all!
Teaching that there are no rules to follow simply isn’t going to cut it. Even those who teach once-saved-always-saved teach that there are rules to follow (though they’ll also say that you never were a Christian to begin with). And the entire New Testament which the Church claims to be teaching from makes it very clear that those who refuse to follow the rules will not inherit the Kingdom of God, but instead the Lake of Fire! So if we were to consistently apply the logic of rules equals salvation by works, then the Bible teaches exactly that! So much for salvation by works being heresy. If the Bible teaches it, then we should too!
But the Bible does not teach salvation by works. It teaches salvation by faith! It teaches that because of our works, we are condemned. And that are works are only capable of condemning us, and cannot save us. The only thing left then is faith. The Bible teaches that by putting our trust in Jesus, all the records of our transgressions of God’s Law are destroyed (our sins are forgiven)!
Romans 3 goes into great detail about why this is, and concludes in verse 31 by asking, “Do we then nullify the law (the rules at the front of the Book) by our faith?” Then answers to that question is answered in that same verse as an absolute “NO!” And it concludes with “we uphold the law.” Here is the verse in it’s entirety: “Do we, then, nullify the law by this faith? Not at all! Rather, we uphold the law.” [Romans 3:31; NIV] In fact, the whole point of being saved by faith is so that we can keep the rules that are in the front of the Book without fear of condemnation if we stumble! But we are warned in Hebrews 10:26 that if we learn that we’re sinning (breaking God’s Law) but we deliberately keep on sinning after we’ve learned the truth, then we have nothing left to atone for our sins.
Is this salvation by works? No! Why not? Because we are not in on the merits of our own works, but by our belief in Jesus. But we can be kicked out by refusing to do the works that are commanded of us. But we are also not kicked out permanently, only until we repent.