How much penance is one to do and what type of a penance? You mentioned below fast, and pray and weep for one's sins.
Is it like 1 year of each? Once a week? Who decides on how long one should do something in order to avoid doing that involuntarily in Purgatory?
God.
But also after we go to Confession, the priest gives us a certain penance to do, which we are supposed to use to conform our hearts to Christ.
Is it not the same in the Lutheran church? I know they have Confession (though we don't recognize it, they still have the form of Confession), my dad was raised Lutheran (LCMS).
Are there instances when God says He does not need penance and will use grace instead?
Penance and grace work together -- there can be no penance without grace.
Of course, we are probably working with different definitions of "grace". I believe that Lutherans use "grace" to mean "mercy". Luther uses the phrase:
"Gottes Huld und Gunst, die er zu uns trägt bei sich selbst" (quoted in
Lehre und Wehre), where he seems to equate
"Huld" (grace) with
"Gunst" (favor) -- "God's grace and favor, by which He carries us to Himself." I don't know if there is a better Lutheran definition of grace but this is my understand.
Catholics use the term "grace" to refer to something much more comprehensive -- the life of God in the soul, grace is God Himself acting on a soul. A soul cannot even turn to God without God granting it the ability to turn to Him (very similar to Wesleyan "prevenient grace" and opposed to semi-Pelagianism, such as held by the Eastern Orthodox). Thus we need God's Grace to be able to have contrition and to do penance.
He could do that, couldn't He? Like ... OK, you are forgiven. See you in Paradise.
That thief on the Cross certainly had more sin than most of people.
Did he bypass Purgatory?
The thief on the cross was not baptized (the Feeneyites* and perhaps some others may object), therefore what he had was the "baptism of repentance" or "baptism of desire" but the same is really true as if he was baptized by water on his deathbed. Baptism remits the stain of Original Sin and both the eternal and temporal punishments due to all the sins you have ever committed -- you are truly made a "new man". Indeed, in the early Church it even became popular to hold off on Baptism until the deathbed -- for example, Constantine converted but wasn't Baptized until they thought he was dying (he recovered). Of course, that's a risky proposition but the idea was to bypass Purgatory this way. Thus all the thief's sins were wiped away by this invisible form of Baptism and he went straight to Heaven (following Christ's Ascension; "this day" he was in Paradise because he went to Hades, 'Limbo',
with Jesus).
A second explanation I could give you would be to emphasize what I said about the path to Heaven being a full and perfect conformity to the image of Christ. That is certainly possible to do in an instant, even though for most people it takes a lifetime (and beyond -- hence, Purgatory).
Dismas, even though he is a sinner, fears God and knows that the horrific execution he is undergoing -- his death -- is a just punishment for the crimes he has committed. He shows evidence here of a great, probably perfect, contrition. Thus even if he had been a follower of Christ at some point and was Baptized**, he could have blotted out all his sins in their entirety by an act of perfect contrition on the cross.
Lk 23:39-43 said:
And one of those robbers who were hanged, blasphemed him, saying: If thou be Christ, save thyself and us. But the other answering, rebuked him, saying: Neither dost thou fear God, seeing thou art condemned under the same condemnation?
And we indeed justly, for we receive the due reward of our deeds; but this man hath done no evil. And he said to Jesus: Lord, remember me when thou shalt come into thy kingdom. And Jesus said to him: Amen I say to thee, this day thou shalt be with me in paradise.
~~~
* Feeneyites -- followers of Fr. Leonard Feeney, who rejected the efficacy of baptism of desire and baptism of blood and promoted the strictest possible interpretation of the dogma "Outside the Church, no salvation" (
Extra Ecclesiam nulla salus). He was excommunicated for a period for disobedience (essentially, failure to appear in court) but was reconciled without having to recant his position.
Their website explains.
** it is not clear when Christ instituted Baptism -- either at His own Baptism, when He proclaimed the necessity of Baptism to Nicodemus or at the Great Commission. The Apostles baptized following Christ's midnight talk with Nicodemus, it is highly unlikely that it is merely John's baptism of repentance they were doing:
After these things Jesus and his disciples came into the land of Judea: and there he abode with them, and baptized. ... When Jesus therefore understood that the Pharisees had heard that Jesus maketh more disciples, and baptizeth more than John, (though Jesus himself did not baptize, but his disciples,)