newadvent.org/cathen/14004b.htm
Excerpt:
The second effect of sin is to entail the penalty of undergoing suffering (reatus pænæ). Sin (reatus culpæ) is the cause of this obligation (reatus pænæ ). The suffering may be inflicted in this life through the medium of medicinal punishments, calamities, sickness, temporal evils, which tend to withdraw from sin; or it may be inflicted in the life to come by the justice of God as vindictive punishment. The punishments of the future life are proportioned to the sin committed, and it is the obligation of undergoing this punishment for unrepented sin that is signified by the “reatus poenæ” of the theologians. The penalty to be undergone in the future life is divided into the pain of loss (pæna damni) and the pain of sense (pæna sensus). The pain of loss is the privation of the beatific vision of God in punishment of turning away from Him. The pain of sense is suffering in punishment of the conversion to some created thing in place of God. This two-fold pain in punishment of mortal sin is eternal (1 Corinthians 6:9; Matthew 25:41; Mark 9:45). One mortal sin suffices to incur punishment. (See HELL.) Other effects of sins are: remorse of conscience (Wisdom 5:2-13); an inclination towards evil, as habits are formed by a repetition of similar acts; a darkening of the intelligence, a hardening of the will (Matthew 13:14-15; Romans 11:8); a general vitiating of nature, which does not however totally destroy the substance and faculties of the soul but merely weakens the right exercise of its faculties.
God does not cause suffering. Suffering is a result of evil and a result of co-operating with evil in the world, that is sin. God has taken the worst effect of our co-operating with evil and has brought forth from it our redemption and Jesus who had never sinned took upon Himself the greatest penalty of suffering so that our suffering may be redemptive in His redeeming work of the Cross.
We owe a debt, each and every one of us and our debt will be paid to the last penny either this side of life or in purgatory the other side of life. We may by God’s good grace pay our debt this side of life by loving Him and by embracing our cross and performing good works in the Living Prayer of our lives. God does not inflict this debt upon us, each man knows written in his own heart the debt he owes and each man will judge his own soul because in the sight of God each man’s debt will be known to him and he will not be able to deny it in th Light of the Goodness of God and so great, so almighty, so powerful and so glorious is He that each man will bend their knee and bow and beg for mercy. Only the truly evil will deny God who is all merciful and refuse to pay their debt and their debt they will measure out upon themselves for all eternity in hell.