Works

But why cannot our good works be the whole or part of our righteousness before God?
Because the righteousness which can stand before the judgment-seat of God, must be perfect throughout and wholly conformable to the divine law; but even our best works in this life are all imperfect and defiled with sin.
Heidelberg Catechism Q. 62.

Salvation is by works. What???! It's true! Our salvation is by the works of Christ! Salvation is truly by the works of Christ on our behalf in his life, death, resurrection and ascension. Our Lord Jesus Christ fulfilled the Law on our behalf and merited eternal life by fulfilling the Law. Those who believe in him shall never perish, but have everlasting life!! Romans 10:4 says "For Christ is the end of the law so that there may be righteousness for everyone who believes." The Greek word 'telos' suggests the goal or purpose of the Law.
Graeme Goldsworthy

Our deeds are not the basis of our salvation, they are the evidence of our salvation. They are not foundation, they are demonstration".
John Piper (Future Grace, p. 364)