For the record:
REMISSION OF SIN
Definition
The true and actual forgiveness of sin. When mortal sin is remitted, this includes pardon of the eternal punishment due to it, but temporal penalty may still remain. When venial sin is remitted, the guilt is removed and as much of the temporal punishment as the person's dispositions warrant from the grace of God.
PLENARY INDULGENCE
Definition
An indulgence that can remove all the temporal punishment due to forgiven sin. No one but God knows for certain when a plenary indulgences is actually gained, because only he knows whether a person's dispositions are adequate. One norm for such dispositions is that "all attachment to sin, even venial sin, be absent." If these dispositions are in any way less than complete, the indulgence will only be partial. The same provision applies to the three external conditions necessary to gain a plenary indulgence: sacramental confession, Eucharistic Communion, and prayer for the intentions of the Pope. If these conditions are not satisfied, an otherwise plenary indulgence becomes only partial. These conditions may be satisfied several days before or after the performance of the prescribed work, though preferably Communion should be received and the prayers offered for the Pope on the same day as the indulgenced work. A plenary indulgence can be gained only once a day.
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