Catholicism: The Cross

Finally we are getting somewhere in the comments section. I feel like I spend half my time trying to get the Catholics to admit to the teachings of their own Church.

Through penance, purgatory and needing to cooperate in their own salvation it is obvious that Catholics deny the completed work of Christ on the cross. While maintaining that it is Christ who saves them with their words, their actions say differently.

This was an analogy given from one of the Catholic commenters:

I understand that we do not save ourselves. Catholics don't believe we save ourselves. [Words]

Catholics believe Jesus saved us by dying on the cross and ascending into heaven. In this way he cleared all the obstacles between humans and God and proceeded to open the gate to heaven. Now the gate's open. We have been saved. Are we just going to sit here and stare at the open gate? No. We must follow Jesus and walk through that gate to enter heaven. Our actions do not "save us", Jesus did, but because have been given free will we must choose to actively follow him. Jesus is not going to drag us through that gate. [Actions]

Likewise from the Catholic Catechism:

“Apart from the cross there is no other ladder by which we may get to heaven.” CCC 618

How does Jesus save if he has only opened the gate? How does he save if he has just provided the ladder? All he has done is provided the means for a person to save themselves by entering the gate or climbing the ladder, depending on which analogy you pick.

In trying to understand this I came upon a comment from a Catholic Apologist on the Envoy Magazine discussion board:

“There have been several theories of the atonement and not one of them is distinctly "Catholic" in an exclusive sense. The only caveat we have is that we do not hold to penal substitution (which has been a favorite theory of the Calvinists). This is the theory that Jesus suffered the punishment for our sins so that we would not have to. We do accept the idea of vicarious atonement in which Jesus suffered on our behalf, but what he did made satisfaction for us so that we would not be punished…The reason that Catholics do not go for penal substitution is because it is tied up with the idea of imputed righteousness….Another problem with penal substitution is that it implies that Jesus has paid the full penalty for sin and that there is no further chastisement to be suffered. This not only eliminates purgatory, it also makes the need for sanctification superfluous. Jesus asked us to take up our Cross and follow him every day. He did not tell us that we had no need to suffer any further. Just the opposite. He warned of persecutions to come and that we would have to "hunger and thirst for righteousness sake." …Finally, if Jesus really was to suffer the penalty for human sin, he would have to be damned to Hell forever. Obviously, that did not happen. And even the sufferings he underwent -- bad as they were -- were not as severe as those suffered by other humans. It was who he was that made the difference. God sacrificed himself for righteousness sake.” Art Sippo (I fixed spelling mistakes from original)

Not only does that quote make no sense to me (it seems contradictory) but that last bolded statement scares me.

Perhaps one of my Catholic commenters can explain to me what the cross accomplished if not the full payment for the penalty of sin. How does a partial payment save anyone?