Culpability (guilt) requires three things:
(1) The act is immoral. (See the “Morality of the Act”.)
(2) Knowledge: The faculty of the intellect understands or should understand that the act is bad.
(3) Consent: The faculty of the will chooses to do the act.
Mortal Sin occurs when the act is gravely wrong: That is, it is not compatible with charity (love of God.)
Venial Sin does not destroy charity, but impedes and lessens charity.
Culpability can be diminished by:
(1) Ignorance (insufficient knowledge)
(2) Weakness (will lacks strength)
But be careful:
• Ignorance is often NOT invincible: e.g., I chose not to study my faith because I spurned the opportunities and preferred to do other things. So it is “my fault” that I don’t know this or that.
• God reads the heart: God knows our weakness and is merciful; we need only turn to him with trust. But His loving mercy is not an excuse to justify our sin by complacently admitting we are weak and using that as an excuse to stop trying. We always have to try, and if we fall, we go straight to God with a contrite heart asking for his forgiveness.
So go to Confession!
• Accuse yourself before the merciful judge in Confession. Confession is not just for mortal sin; frequent confession is good for all souls. As Jesus tells St. Faustina, “Tell souls not to place within their own hearts obstacles to My mercy, which so greatly wants to act within them. My mercy works in all those hearts which open their doors to it. Both the sinner and the righteous person have need of My mercy. Conversion, as well as perseverance, is a grace of My mercy.” (Diary of St. Faustina, #1577).
• Don’t take “chances” on mortal sin. Is it objectively wrong? Go to Jesus in confession; he will forgive you and strengthen your will and illuminate your mind so you can be fully human as He intends!
Jesus’ words to St. Faustina on Confession:
Write, speak of My mercy. Tell souls where they are to look for solace; that is, in the Tribunal of Mercy [the Sacrament of Confession] There the greatest miracles take place [and] are incessantly repeated. To avail oneself of this miracle, it is not necessary to go on a great pilgrimage or to carry out some external ceremony; it suffices to come with faith to the feet of My representative and to reveal to him one’s misery, and the miracle of Divine Mercy will be fully demonstrated. Were a soul like a decaying corpse so that from a human standpoint, there would be no [hope of] restoration and everything would already be lost, it is not so with God. The miracle of Divine Mercy restores that soul in full. Oh, how miserable are those who do not take advantage of the miracle of God’s mercy! You will call out in vain, but it will be too late. (Diary of St. Faustina, #1448)