The Enchiridion 81
81 There are Two Causes of Sin, Ignorance and Weakness; And We Need Divine Help to Overcome Both PL 40, 271
I shall now say this, which I have often said before in other places of my works. There are two causes that lead to sin: either we do not yet know our duty, or we do not perform the duty that we know. The former is the sin of ignorance, the latter of weakness. Now against these it is our duty to struggle; but we shall certainly be beaten in the fight, unless we are helped by God, not only to see our duty, but also, when we clearly see it, to make the love of righteousness stronger in us than the love of earthly things, the eager longing after which, or the fear of losing which, leads us with our eyes open into known sin. In the latter case we are not only sinners, for we are so even when we err through ignorance, but we are also transgressors of the law; for we leave undone what we know we ought to do, and we do what we know we ought not to do. Wherefore not only ought we to pray for pardon when we have sinned, saying, “Forgive us our debts, as we forgive our debtors;” but we ought to pray for guidance, that we may be kept from sinning, saying, “and lead us not into temptation.” And we are to pray to Him of whom the Psalmist says, “The Lord is my light and my salvation:” my light, for He removes my ignorance; my salvation, for He takes away my infirmity.
Peccati causae duae, ignorantia et infirmitas, quas nemo vincit nisi divinitus adjutus. Hoc nunc dicam, quod quidem et in aliis opusculorum meorum locis saepe jam dixi. Duabus ex causis peccamus; aut nondum videndo quid facere debeamus, aut non faciendo quod debere fieri jam videmus: quorum duorum illud ignorantiae malum est, hoc infirmitatis. Contra quae quidem pugnare nos convenit: sed profecto vincimur, nisi divinitus adjuvemur, ut non solum videamus quid faciendum sit, sed etiam accedente sanitate delectatio justitiae vincat in nobis earum rerum delectationes, quas vel habere cupiendo, vel amittere metuendo, scientes videntesque peccamus; jam non solum peccatores, quod eramus etiam cum per ignorantiam peccabamus, verum etiam legis praevaricatores, cum id non facimus quod faciendum, vel facimus quod non faciendum esse jam scimus. Quapropter non solum si peccavimus ut ignoscat, propter quod dicimus, Dimitte nobis debita nostra, sicut et nos dimittimus debitoribus nostris; verum etiam ne peccemus ut regat, propter quod dicimus, Ne nos inferas in tentationem ; ille rogandus est, cui dicitur in Psalmo, Dominus illuminatio mea et salus mea ; ut illuminatio detrahat ignorantiam, salus infirmitatem.