I’ll take a shot at this.
God is eternal. He is infinitely loving, and infinitely just. Through His infinite love, He created us finite creatures. Since the fall, we have sinned and offended an infinite God. As finite creatures, there is absolutely nothing we can do to “make up” for those offenses, since they offended an infinite God.
The wages of sin is death.
What we deserve for our sins is eternal damnation. But God doesn’t want that for us, so He made a way for us to be reconciled to Him. Only an infinite person can satisify an offense against God. So He sent the second person of the Trinity to be born and die for our sins. So now we have the death of an infinite person, and for an infinitely just God, that is an acceptable atonement for sin.
Now in the confessional, Christ hears our sins, and our request to be forgiven. As the one mediator between God and man, Christ tells the Father that we should be forgiven of our sins. The Father says to the Son “Why should I forgive that person? There is nothing they can do to satisfy my infinite justice.” Then Christ points to his death on calvary and replies “That’s why. The wages of sin is death, and I paid that price for this person.” The Father says “Very well. Instruct the priest to give absolution.”
I hope I didn’t get anything theologically wrong here. Books can be written on this subject, vast as it is.
