I am differentiating from our redemption which of course was immediately effected at Calvary. Jesus’ death meant the door to heaven was no longer barred to us. But though the door to heaven is opened I still must follow the correct path to arrive there. I can not even get on that path without the grace of God. His grace also makes it possible to stay on the path by giving me the faith to trust wholly that He alone is the way. Salvation is God's greatest gift and promise to us. He desired us enough to suffer death upon the Cross. But just as my personal sin nailed that cross I am personally saved by His atonement. Which means I must personally encounter Him. You encounter Him through the Bible, prayer and worship. I encounter Him through the Bible, Church, prayer, worship and the sacraments. Especially the Eucharist. Christ wants us to have a relationship with Him. He knows and loves each of us. Anything that keeps you from the love of Christ must be rejected. No matter how good that thing may seem. I am Catholic belief in the real presence and the sacrifice of the Mass cements my belief and love of Christ. For you such beliefs cause scandal and separate you from that love. Since you are not Catholic you are not bound to Catholic dogma so I say go in peace and serve Him where it gives you the best nourishment for your soul.
That's a great question and the answer has to do with the different meanings Protestants and Catholics attribute to justification and sanctification.
For the Catholic, they are much the same thing. The RCC teaches that both justification and sanctification are ongoing throughout life, i.e. men must obey and repent in order to receive God's grace.
According to the historic Protestant faith, we believe Scripture tells us that justification is the one-time atonement Christ made for His flock. Since God ordained all that comes to pass, He likewise ordained the names of the elect from before the foundation of the world. Two thousand years ago He determined that Christ, God Himself, would come to earth, suffer for the sake of His sheep, die for their sins and be resurrected to prove it all true so that you and I could stand before God acquitted of our sins, blameless by the covering of blood of Jesus Christ.
Much more then, being now justified by his blood, we shall be saved from wrath through him. For if, when we were enemies, we were reconciled to God by the death of his Son, much more, being reconciled, we shall be saved by his life. And not only so, but we also joy in God through our Lord Jesus Christ, by whom we have now received the atonement. Wherefore, as by one man sin entered into the world, and death by sin; and so death passed upon all men, for that all have sinned: (For until the law sin was in the world: but sin is not imputed when there is no law. Nevertheless death reigned from Adam to Moses, even over them that had not sinned after the similitude of Adam's transgression, who is the figure of him that was to come. But not as the offence, so also is the free gift. For if through the offence of one many be dead, much more the grace of God, and the gift by grace, which is by one man, Jesus Christ, hath abounded unto many. And not as it was by one that sinned, so is the gift: for the judgment was by one to condemnation, but the free gift is of many offences unto justification. For if by one man's offence death reigned by one; much more they which receive abundance of grace and of the gift of righteousness shall reign in life by one, Jesus Christ.) Therefore as by the offence of one judgment came upon all men to condemnation; even so by the righteousness of one the free gift came upon all men unto justification of life. For as by one man's disobedience many were made sinners, so by the obedience of one shall many be made righteous." -- Romans 5:8-19 "But God commendeth his love toward us, in that, while we were yet sinners, Christ died for us.
Sanctification, however, is a life-long process whereby the indwelling Holy Spirit regenerates our hearts and turns our eyes from sin to God.
We will never be perfect; we will always sin. It's our human nature. But by the grace of God, we will sin less and less as the Holy Spirit makes Himself known in our hearts and guides our steps.
God expects us to acknowledge this fact. And so we ask forgiveness every day for every sin we commit, confident that every sin has already been forgiven by His sacrifice. Just like we ask for a repentent heart and an obedient will. Just like we are instructed to pray for everything we want, all with God knowing exactly what we need before we ask Him. By the grace of God, those gifts are given to us. As William Buckley once wrote, gratitude is the proper perspective of the Christ mind. Coming from a Roman Catholic, I thought that was very Reformed of him. 8~)
Wherein in time past ye walked according to the course of this world, according to the prince of the power of the air, the spirit that now worketh in the children of disobedience: Among whom also we all had our conversation in times past in the lusts of our flesh, fulfilling the desires of the flesh and of the mind; and were by nature the children of wrath, even as others. But God, who is rich in mercy, for his great love wherewith he loved us, Even when we were dead in sins, hath quickened us together with Christ, (by grace ye are saved;) And hath raised us up together, and made us sit together in heavenly places in Christ Jesus: That in the ages to come he might shew the exceeding riches of his grace in his kindness toward us through Christ Jesus. For by grace are ye saved through faith; and that not of yourselves: it is the gift of God: Not of works, lest any man should boast. For we are his workmanship, created in Christ Jesus unto good works, which God hath before ordained that we should walk in them." -- Ephesians 2:1-10"And you hath he quickened, who were dead in trespasses and sins;
It all comes down to trust. Either we trust that Christ has paid the penalty for our sins, or we don't.
I really enjoy the Westminster Larger Catechism's perspective, particularly its first question...
Question 1: What is the chief and highest end of man?
Answer: Man's chief and highest end is to glorify God, and fully to enjoy him forever.