James 2:10-12
10For whoever keeps the whole law but fails in one point has become accountable for all of it. 11For he who said, "Do not commit adultery," also said, "Do not murder." If you do not commit adultery but do murder, you have become a transgressor of the law. 12So speak and so act as those who are to be judged under the law of liberty.
Once a person commits one sin, they are condemned. they need FORGIVENESS. Works could only save if someone kept the Law perfectly their entire life; only if they never sinned.
Since that is not possible, forgiveness must be granted. That's an act of mercy on the part of the forgiver, not what is due to the sinner for other good works racked up to his account.
Salvation is a gift given out of mercy. You don't work to earn a gift or earn mercy. If you earned it, it wouldn't be mercy, it would be wages.
That is true. If he commits one sin, he has to obtain absolution for that sin form a priest (2 Corinthians 5:18, John 20:21-23). Following that, he can go on on the journey of good works.
[cites John 6:29]
"That you believe in him whom he has sent" is certainly a requirement of faith, but that is not the only work required of us. Where is it commanded? Review Matthew 5-7.