[ealgeone]

As for Christ once sacrifice, the doctrine of mortal and venial sin does not negate it or contradict it. Christ dying on the Cross is the means thru which all and every sin committed for the entire human history will be forgiven.

If this be the case why the big issue of the differing types of sins if all sins are forgiven through Him?

[CTrent1564]

ealgeone:

The difference is that mortal sins are so evil, that once one allows himself to be tempted to commit them, and not respond to conscience given to them by the Holy Spirit to repent, one severs communion with God. In other words, in Catholic Theology, the hey have rejected God’s Grace and totally turned away from it. Now, Christ will forgive mortal sins, yes, but the danger for individuals is once you go down that path, you are heading the wrong way.

Venial sins are just the daily faults that all of us have, we may get upset with someone, but we don’t let that get so into our hearts that we go commit violent acts towards the individual.