The thing about penance is this, you do good works so that you
can be made right with God, never in the bible has this ever been
said. You are made right with God through the blood of Jesus
only.
It is because you are already made right with God that you then do
the good works. Faith must come first, not works.
As part of the articles of catechism in the part about penance it
says that it is only when the priest gives you absolution then will
you receive God's forgiveness. This makes your forgiveness
dependent on a man and not Jesus. God's forgiveness to us in not
controlled or conditional upon a mere man forgiving us. It is
conditional upon us accepting His Grace and what Jesus did for
us.
Doing penance is doing something which is decided by the priest who
"determines" how bad your sin supposedly is... sin, is sin, little
sin, big sin, it is all the same to God. It is sin, God does not
measure sin. So who gave this man the right to determine the depth
of our sin and then set for us the appropriate work to receive our
forgiveness? This then makes what Jesus did for us to no effect. If
we could work for our forgiveness, then we would not need Jesus.
Even in the OT, the Isrealites only atonement and forgiveness for
sin was a pure sacrifice. This is God's way and it still has not
changed.
In the bible Jesus says, I have not come to abolish the law, but to
fulfill the law.
It also says that in the articles of catechism, that doing this
penance contributes to our forgiveness of our sins. Works have
never and will never contribute to the forgiveness of our
sin.
The articles of catechism also demand satisfaction, that the sinner
"expiate" his sin by doing works. Our sins were already "expiated"
when Jesus died for us.