Dragging out that misstatement really needs to stop. Let’s look at what was really said.
James 2:19 Thou believest that there is one God; thou doest well: the devils also believe, and tremble.
Notice it says that the devils also believe there is one God. It does NOT say they believe IN God, or ON God. On the other hand one is saved by belief ON the Lord Jesus Christ.
The jailor was told “believe on the Lord Jesus Christ and you will be saved”. That belief and trust carries a promise of not only salvation but of a changed life that includes acting on that faith just as Abraham did. It was Abrahams faith that saved but his actions that proved his faith.
Demons/devils believe there IS one God but they don’t believe IN or ON that one God. Huge difference.
>>So, holiness is a condition to perfection.<<
It’s Christ’s holiness we are covered with not any holiness of our own.
Galatians 2:20: Paul speaks of himself and all true Christians: "I have been crucified with Christ; it is no longer I who live, but Christ lives in me."
It’s not “our” faith but Christ’s faith in us that we live.
But of him are ye in Christ Jesus, who of God is made unto us wisdom, and righteousness, and sanctification, and redemption: That, according as it is written, He that glorieth, let him glory in the Lord. (1 Corinthians 1:30-31)
And be found in him, not having mine own righteousness, which is of the law, but that which is through the faith of Christ, the righteousness which is of God by faith: (Philippians 3:9)
It’s not our faith or righteousness but Christ’s faith and righteousness working through us that is ours when we believe on Him. How could we be more prefect than the perfection of Christ in us? Through the gift of grace that is how the Father sees us.
It's not even us who does it but God in us.
For all Catholics sneer at the total depravity of man, they need to get a much better grip on the corruption of our nature and our slavery to sin that keeps us from being able to do anything good on our own.
There is this underlying current in Catholic thought that they can go through life and not sin for periods of time. Like they are good enough, which is why they think their works can contribute to their salvation. They don't see that even our best works in and of ourselves is corrupted with sin and therefore unacceptable to God.
They are missing completely the meaning of the wedding feast and the garments, which are the righteousness of Christ imputed to us. (Matthew 22)