Salvation is either 100% of God or there is some amount of cooperation on the part of the sinner. Jesus either paid the price in full, or there is still some work to be done.
The Catholic model of salvation is one of cooperation between God and the sinner. Jesus’s perfect righteousness and death on the cross merited the grace for the sinner to justify (make righteous) himself.
This grace merited by Jesus (sanctifying grace) is given in increments starting with Baptism and is continued to be merited by the sinner through good works (sacraments, acts of charity, etc.). But sanctifying grace can also be lost through sin, and if you die without sanctifying grace in your soul, you will not make it to heaven.
"Once you have supernatural life, once sanctifying grace is in your soul, you can increase it by every supernaturally good action you do: receiving Communion, saying prayers, performing the corporal works of mercy. Is it worth increasing sanctifying grace once you have it; isn’t the minimum enough? Yes and no. It’s enough to get you into heaven, but it may not be enough to sustain itself. It’s easy to fall from grace, as you know. The more solidly you’re wed to sanctifying grace, the more likely you can withstand temptations.
And if you do that, you maintain sanctifying grace. In other words, once you achieve the supernatural life, you don’t want to take it easy. The minimum isn’t good enough because it’s easy to lose the minimum. We must continually seek God’s grace, continually respond to the actual graces God is working within us, inclining us to turn to him and do good.” Catholic.com
"No one can merit the initial grace which is at the origin of conversion. Moved by the Holy Spirit, we can merit for ourselves and for others all the graces needed to attain eternal life, as well as necessary temporal goods." CCC 2027
"We can therefore hope in the glory of heaven promised by God to those who love him and do his will. In every circumstance, each one of us should hope, with the grace of God, to persevere "to the end" and to obtain the joy of heaven, as God's eternal reward for the good works accomplished with the grace of Christ..." CCC 1821
Since the initiative belongs to God in the order of grace, no one can merit the initial grace of forgiveness and justification, at the beginning of conversion. Moved by the Holy Spirit and by charity, we can then merit for ourselves and for others the graces needed for our sanctification, for the increase of grace and charity, and for the attainment of eternal life. Even temporal goods like health and friendship can be merited in accordance with God's wisdom. These graces and goods are the object of Christian prayer. Prayer attends to the grace we need for meritorious actions. CCC 2010
"Fully incorporated into the society of the Church are those who, possessing the Spirit of Christ, accept all the means of salvation given to the Church together with her entire organization, and who - by the bonds constituted by the profession of faith, the sacraments, ecclesiastical government, and communion - are joined in the visible structure of the Church of Christ, who rules her through the Supreme Pontiff and the bishops. Even though incorporated into the Church, one who does not however persevere in charity is not saved. He remains indeed in the bosom of the Church, but 'in body' not 'in heart.'" CCC 837
"The Church affirms that for believers the sacraments of the New Covenant are necessary for salvation. "Sacramental grace" is the grace of the Holy Spirit, given by Christ and proper to each sacrament. The Spirit heals and transforms those who receive him by conforming them to the Son of God. The fruit of the sacramental life is that the Spirit of adoption makes the faithful partakers in the divine nature by uniting them in a living union with the only Son, the Savior." CCC 1129
This cooperation with God by the sinner to insure salvation is quite different than the Protestant understanding of justification which relies on the completed work of Christ on the cross to reconcile the sinner to God (which is obatined by faith alone). Sadly, in reading Catholic material, the Protestant teachings on salvation and justification as described by Catholic literature seem to be somewhat misunderstood and inaccurate. I have some interesting quotes to share in my next post.