Updated: Mar 9, 2021
By Luke Lancaster
Non-Catholic Christians have a false understanding of Christ's atonement. They claim that when we become saved, Christ's atonement cleanses us of all our sins: past, present, and future. If that was the case, then there would be no need for purgatory, for all punishment due to sin would be eradicated. This is totally incorrect, though. For when we repent of our sins, get baptized, and become joined to Christ's suffering and death, only our past sins are forgiven. We become "perfect" in the words of Hebrews 10:14, headed on the path towards Heaven, but only for the moment.
When a saved person sins, are those sins already taken care of? If so, then Scripture would say so. But it does not. It presents us as people who have had only our past sins forgiven. 2 Peter 1:9 says that man has been "cleansed from his old sins." If our future sins had been cleansed, shouldn't this passage have said "old and new sins"?
Similarly, if man's future sins had been forgiven, then he would be presented as a man that could not get dirty. Yet, St. Peter compares Christians who fall into worldly sins to a pig that has been cleaned off from the mud, but only to return to the mud. He says,
"For if, after they have escaped the defilements of the world through the knowledge of our Lord and Savior Jesus Christ, they are again entangled in them and overpowered, the last state has become worse for them than the first. For it would have been better for them never to have known the way of righteousness than after knowing it to turn back from the holy commandment delivered to them. It has happened to them according to the true proverb, The dog turns back to his own vomit, and the sow is washed only to wallow in the mire" (2 Peter 2:20-22).
If we get new mud on us, we need to constantly go back to Jesus's passion. We need to repent and beg God for forgiveness once again. In the words of 1 John 1:9, "If we confess our sins, he is faithful and just, and will forgive our sins and cleanse us from all unrighteousness." This does not only happen once! For our future sins have not been pre-forgiven!
The sacrifice of Jesus Christ on the wood of the cross of Calvary is still being applied to us, perfecting us of past sin that will never return. When we stand before God at the end of time, God will not remember our past sins that were washed in the blood of the Lamb at baptism. But any sins which we committed after baptism, we needed to repent and go to Confession over.
If we do not repent of every sin we committed after baptism, then those sins remain, and need to be dealt with either here on earth or beyond earth (purgatory). We also need to keep in mind that even if we repent of sins committed after baptism, we need to repent perfectly. For if we are half-hearted in our sorrow for sin, then there will be some kind of punishment awaiting for us. Whether that be here on earth, or beyond in purgatory.