Maybe justify isn't the right word.
Christ's work on the cross justifies us. Our good works of faith illustrate our ongoing sanctification by the Holy Spirit.
"Justify" is one of those words we need to protect the real meaning of lest Rome rewrite everything important, like grace and forgiveness and mediator.
The depravity of man and grace in Christ by which the unGodly are justified (Rm. 4:5) must indeed be stressed, However as said (and needs to be in this superficial age), there is more than one kind of faith, and as 1John and multiples texts reveal, and reformers taught, justifying faith is a faith that will and does effect obedience towards its Object, which includes repentance when convicted of not doing so. Belief that does not affect change our life is not faith but fantasy.
Moreover, while the elect are accounted righteous by faith and are the children of God, yet because they are children and faith must be true, thus God chastens them to repentance, if need be, that they be not condemned with the rest of the world, (1Cor. 11:32) as apostates. (Gal. 5:1-14; Heb. 10:39-39)
And in contrast to sins that are past, what we do as believers will be rewarded or suffer loss, not in some purgatory commencing at death, but at the judgment seat of Christ at His return.
The error of Rome here is not simply statements in her plethora of pronouncements which foster hope of eternal life partly based on having morally earned it (which is also true in institutionalized Protestantism), but effectually promoting faith in herself to eventually obtain Heaven for the most nominal of Catholics, including abortion and homosexual promoting pols.