Why do your works fail to justify you before God? First, keep in mind justification is more than being forgiven. It’s the elimination of any record of wrong doing. Whereas forgiveness absolves me of the consequences of sin, justification imparts a right-standing before God “just-as-if-I’d” never sinned.
This means justification can only come after my sins have been atoned for - Romans 6:23, “For the wages of sin is death.” This means you can work hard to be found right before God and still fall short, because there is nothing you can fundamentally do to atone for sin apart from dying an eternal death. No work but death atones for sin!
And yet, while this explains why there is fundamentally nothing you can do to justify yourself before God, it also explains why your justification before God has been made possible through Jesus’ atoning work on the cross.
Because Jesus satisfied the debt for your sin through His death, faith in His work can also justify you before God. You see salvation came not through your works, but as a gift - God Grace!
In light of the legalistic tendency to emphasize what you do for God, never forget you’re works have never played a role in your atonement for sin or justification before God… Instead, you’ve been forgiven and declared righteous (justified) for one reason alone… Faith in the work of Jesus!
Remember the core problem of legalism is not a failure to believe the Gospel, but a failure to fully trust that the Gospel works! While the law failed to atone, justify, and save - Jesus succeeded meaning… grace really does change everything!