The Roman Catholic doctrine of Justification does not differ rather widely from the Protestant understandings of the doctrine that differ rather widely from each other.
We are on a Baptist website, so I will quote from the 1689 Baptist Confession. I have left out the proof-texts, but they can be found at
Of Justification — The 1689 Baptist Confession of Faith
11:1
Those whom God effectually calls, he also freely justifies, not by infusing righteousness into them, but by pardoning their sins, and by accounting and accepting their persons as righteous; not for anything wrought in them, or done by them, but for Christ's sake alone; not by imputing faith itself, the act of believing, or any other evangelical obedience to them, as their righteousness; but by imputing Christ's active obedience unto the whole law, and passive obedience in his death for their whole and sole righteousness by faith, which faith they have not of themselves; it is the gift of God.
11:2
Faith thus receiving and resting on Christ and his righteousness, is the alone instrument of justification; yet is not alone in the person justified, but is ever accompanied with all other saving graces, and is no dead faith, but works by love.
11:3
Christ, by his obedience and death, did fully discharge the debt of all those who are justified; and did, by the sacrifice of himself in the blood of his cross, undergoing in their stead the penalty due to them, make a proper, real, and full satisfaction to God’s justice in their behalf; yet, in as much as he was given by the Father for them, and his obedience and satisfaction accepted in their stead, and both freely, not for anything in them, their justification is only of free grace, that both the exact justice and rich grace of God might be glorified in the justification of sinners.
This is at variance with the official Roman Catholic 1994 Catechism which I quoted earlier, but here you are again:
'Justification is not only the remission of sins, but also the sanctification and renewal of the interior man (paragraph 1989).
Indeed, the Roman Catholic doctrine of Justification is nearly identical to the Lutheran doctrine.
There was a "Joint declaration on the Doctrine of Justification" between the Roman Catholic Church and the Lutheran World Federation. They came out with a form of words to which the Lutherans could say, "This is salvation by faith alone" and Rome could say, "This is not salvation by faith alone." They then claimed to be in agreement!
However, the Roman Catholic doctrine of Justification differs greatly from the Reformed Doctrine of Justification and very significantly from most Baptist doctrines of Justification—especially those that are heavily influenced by Reformed theology.
Absolutely!
The most substantial difference between the Roman Catholic doctrine of Justification and the many Baptist doctrines of Justification is that the Catholic Church distinguishes between initial justification and ultimate justification where the very large majority of Baptists (those who teach OSAS) make no such distinction.
Either one is justified or one is not. There cannot be an 'initial justification' if at the end one is to be told that one is not justified after all. That is like an accused man being found not guilty, but then being slapped in jail anyway. And Justification is a legal term: Deut. 25:1.
'If there is a dispute between men, and they come to court, that the judges may judge them, and they justify the righteous and condemn the wicked....'
Another significant difference between the Roman Catholic doctrine of Justification and the many Baptist doctrines of Justification is that the Catholic Church emphasizes the quality of saving faith teaching that faith without “hope” and “love” is not biblical faith.
That is contrary to what the Bible teaches. Acts 16:31.
"Believe on the Lord Jesus Christ and you will be saved." Hope and love will follow, but at the point of Justification, it is faith alone.
Nonetheless, the quotes that I presented from the New American Bible and the commentaries on the Greek text of Romans by Boylan and by Fitzmyer clearly show that the Roman Catholic doctrine of Justification does not differ widely from the Protestant understandings of the doctrine that differ rather widely from each other.
What they perhaps show is that Rome's understanding on these things varies widely.
Some years ago, I attended a Protestant Bible study that was also attended by a Roman Catholic Priest. The priest’s ignorance of the Bible and Roman Catholic dogma from a biblical perspective was shocking. At about the same time, I had a 90-minute conversation with Monsignor G******* who was the rector of a large cathedral. We talked about Roman Catholic dogma and his personal beliefs where they agreed and where they differed from that dogma. However, what really struck me was the unmistakable overriding presence of Christ in His life. That 90-minute conversation changed my life!
I am not saying that all Roman Catholics are lost. I am saying that many of their doctrines are unbiblical. God is not interested in denominations; those who believe on the Lord Jesus Christ for salvation will be saved. But if your Monsignor is relying on his baptism as a tiny baby or his attendance at the mass or anything except the shed blood and perfect righteousness of Christ, he is on shaky ground.