Among those who believe in the existence of God, there is the almost universal idea that we can do something meritorious to gain God’s favour and eternal life, often by religious ritual, legalistic obedience etc.. In the New Testament, this error is known as "works" or "works of the law." It is the absolute antithesis of salvation by grace.

Now we know that whatever the law says, it says to those who are under the law, that every mouth may be stopped, and all the world may become guilty before God. Therefore by the deeds of the law no flesh will be justified in His sight, for by the law is the knowledge of sin. Rom 3:19-20

We should be careful to distinguish between the law itself and the works of the law.
Rom 9:32 Eph 2:8-10

Many people think that God will somehow balance our good against the bad, but this fails to take God's justice into account.

Any teaching which mixes human merit or works with grace is no longer grace.
Rom 11:6