First rule of Bible interpretation is to let the Bible as a whole interpret the Bible, instead of individual text. I think that Jesus was here because our works could not save us. Isaiah 64:4 "our righteousness are as filthy rags." We would not need Jesus if we could save ourselves. Ephesians 2:9 "not by works so no one can boast". I believe Jesus here is saying what James said in his epistle "faith without works are dead". Same principle works does not save us. It does play apart which some people do not understand. With future reward in Heaven and the degree of punishment in hell.
If only I had a dollar for every time I saw the righteousness as filthy rags thing. It's as if they NEVER actually read Isaiah 64. Are you even aware of the context of Isaiah 64:6? (That's 6, not 4) Have you read Isaiah 66? It's amazing the way antinomians interpret this, it is clearly about the time that Israel is destroyed BECAUSE her righteousness is insufficient and the Israelites have committed sin. It has absolutely nothing to do with the idea that righteousness is always considered "dirty rags", it actually does in fact anger me to see how convoluted the interpretation of this verse gets by the mainstream Christian establishment, I can't explain the frustration in seeing them use that verse to justify their doctrine that works are not necessary even when Jesus plainly says that works are necessary, it's as if they have not read Isaiah 64 and think they can just make up whatever context they want of that verse. How they interpret it to mean that righteousness itself is as dirty rags, completely going against all the other things in the Bible saying about righteousness, is a true testimony to the total dishonesty and scriptural ignorance of antinomians.
When they use Isaiah 64:6, it's an immediate give-away that they shudder at the thought of actually reading the passages in question and go by cherry picked out-of-context versions. For example, the whole of 64:6 says:
All of us have become like one who is unclean,and all our righteous acts are like filthy rags;
we all shrivel up like a leaf,
and like the wind our sins sweep us away.
What does it mean to "become like one who is unclean"? Exactly? Given the context of the preceding verses, it's obviously implying that the Israelites have sinned. Therefore, their "righteous acts" are mixed with dirty acts. Clearly, it says "Our sins sweep us away". I think there's a reason why this verse is so often cherry picked without the full verse.
And then what's truly great, is that while thinking Isaiah 64 implies works are not important (which is the exact opposite of the meaning of the passage), they then go on to completely ignore Isaiah 66 which clearly defines that Law obedience is necessary after the events of the Messianic age. Do they think that Isaiah 66 no longer counts?
Care to quote the entirety of Isaiah 64 or would you like to admit that this is a totally wrong interpretation of the passage?
Also, Ephesians is most likely not even by Paul to begin with and was probably written by Paulinists after the schism between Ebionites/Nazarenes and the Paulinists to support an Anti-Law view. As for what James meant by "Faith without works is dead", you should also see how he said that faith without works "Cannot save". Therefore, works are not just some "fruit of the saved" as numerous antinomians say, and often when asked what kind of "works" are exclusive to the saved Christian, they refuse, absolutely refuse to answer what kind of specific works are involved.
Personally I'd consider any religion preaching antinomianism as a "cult", I have in fact met many a Christian who thinks they can go on to do whatever they want because of this, and they can be much worse liars, thieves, fornicators, drunkards, etc than non-Christians probably because of this idea that the mainstream churches propagate that their "Righteousness is as filthy rags".