You can be forgiven for a sin by praying to God and asking forgiveness. However, the way you KNOW you have been forgiven is when the Priests says the words of absolution. In this manner, God gives us a way to know for sure, with no doubt, that we have been forgiven.
Confession also gives a means to make reparation for our sin via the penance that is assigned by the Priest.
Venial Sins - Venial sins are slight sins. They do not break our friendship with God, although they injure it. They involve disobedience of the law of God in slight (venial) matters. If we gossip and destroy a person’s reputation it would be a mortal sin. However, normally gossip is about trivial matters and only venially sinful.
Mortal Sins - Mortal sin is called mortal because it is the “spiritual” death of the soul (separation from God). If we are in the state of grace it loses this supernatural life for us. If we die without repenting we will lose Him for eternity. However, by turning our hearts back to Him and receiving the Sacrament of Penance we are restored to His friendship. Catholics are not allowed to receive Communion if they have un-confessed mortal sins.
There are three conditions that make an act a mortal sin:
An act of grave matter that is…
Committed with full knowledge and…
So if you have committed a mortal sin you do need to go to confession in order to be absolved. Please note that absolution will absolve you from the guilt of sin but a temporal punishment may remain. God is the only one who can decide what a temporal punishment will be and if it is remitted through penance or indulgences. Potentially, all temporal penalties can be remitted. The Church recognizes that Christ and the saints are interested in helping penitents deal with the aftermath of their sins, as indicated by the fact they always pray for us (Heb. 7:25, Rev. 5:8). Fulfilling its role in the administration of temporal penalties, the Church draws upon the rich supply of rewards God chose to bestow on the saints, who pleased him, and on his Son, who pleased him most of all.
Venial sins can be forgiven by asking God directly for forgiveness and can also be forgiven during the penitential rite at Mass. The penitential rite is when the priest invites us to reflect on our sins so that we can make confess them and be in a state of grace during Mass. An example of the penitential rite is the Confiteor, “I Confess to all mighty God…” or the priest has several options he can pull from scripture.
Special Note: It is a good idea to go to confession once a month (not required just a suggestion) and to confess the venial sins that you can remember to a priest. There are special graces that come with confession so it is always a blessing to partake in them.
The Church teaches that while God gives us sacraments, He, Himself, is not bound by those sacraments. So it is possible to be forgiven outside the sacrament of priestly confession…however, this is the only ordinary method from which you have 100% assurance that you have been forgiven.
Confessing to a priest sounds scary for people who have never done it, but I can tell you that it should not be because the priest is not the boogey man, he genuinely wants to help you. He will likely give you some sort of simple penance that is relevant to your situation.
Example: “Father, I have been unruly to my spouse and caused strife in our relationship”
Penance:*** I want you to sit in the pews, look at the crucifix for at least 5 minutes while praying and asking the Lord to help you understand your wife better.
Easy as 1,2,3 and beneficial too.
And I have been told that if your routine is to go to confession every Saturday, yet you die on Friday with full intent to go to confession the next day, salvation will still be attained. So it’s more than a ritual, it’s about the disposition of our hearts as well.
Good question. Penance is more for the temporal punishment of sin, but it also makes repairs our separation from the Church. Penance is a part of justice. I’m not 100% sure how to answer this question, so I’ll just point you to the pertinent section of the Catechism. Begin at 1430, and hone in on 1450, 1459, and 1460. scborromeo.org/ccc/p2s2c2a4.htm#1460
God forgives a sinner the instant that person manifests perfect contrition, i.e., contrition motivated by love of God. However, we are not necessarily the best judge as to whether our contrition is perfect or imperfect. In the sacrament of Confession, a sinner needs only to manifest imperfect contrition to receive absolution from a priest. Best to error on the side of caution and assume your contrition is only imperfect and go confess to a priest.