Like, I see why Perfect Contrition is necessary outside Confession and outside access to the sacraments more generally (like in the case of the Old Covenant. Think of David’s psalm of repentance).
Because Perfect Contrition is sorrow out of love of God. And justification is just that: The transformation of the interior life into one of Love of God (virtue of Charity ~ Sanctifying Grace). I see the inherent connection here.
But in Confession, you do not need to be sorry out of love of God. You still need genuine attrition, at least: repentance out of hatred for sin, or fear of hell, etc. But this is enough to justify one even in the state of Mortal Sin, if one goes to Confession.
So what’s the connection?
Outside of Confession, now or before Christ:
Sorrow for Love of God (Perfect Contrition) — --- — > Forgiveness/Justification and infusion of Virtue of Charity
In Sacrament of Confession:
Sorrow out of Attrition (less than Love for God) + ___________________ — --- — > Forgiveness/Justification and infusion of Virtue of Charity
What is this blank? What is it in the Sacrament that makes up for the absence of Perfect Contrition?
What is it about the Sacrament that does not allow God to forgive someone with just imperfect contrition, outside of Confession?