Chapter VII: Sins of Commission and Omission, § 25.
CHAPTER VII: ON SINS OF COMMISSION AND OMISSION
§ 25. The second division of actual sins was this: some sins are of commission; some are of omission. The basis for this division lies in the divine Law itself, which not only forbids evil but also commands good. Not only does the Law command one to depart from evil, but it also orders one to do good. Therefore surely one sins against the Law not only by committing evil acts but also by omitting good ones. James 4:17: “To him who knows what is good and does not do it, it is sin.” Matt. 25:42: “I was hungry, and you did not feed Me; I was thirsty, and you gave Me nothing to drink,” etc. 1 John 3:17: “He who has the wealth of this world and sees his brother in need, yet closes his heart against him, how does the love of God abide in him?” The sentence of this sin is described in Matt. 3:10 and 7:19: “Every tree which does not produce good fruit is cut down and thrown into the fire.” Matt. 25:30: “Cast the worthless servant into outer darkness!” Luke 12:47: “The servant who knew his master’s will and did not prepare himself will receive many blows.” Luke 13:7: “Cut down the fruitless tree.” John 15:2: “The Father in heaven will remove every branch which bears no fruit.” Ambrose: “If you have not trembled, you have perished.” Nazianzen: “May the goats set on the left hand terrify you, not because they ravage, but because they have not trembled.”
Is a sin of omission voluntary?
§ 26. Some establish a twofold sin of omission, for, at times, good things are omitted, and at times adversities are rejected. The former comes from corrupt concupiscence which inclines the will to that omission; the latter, from a wrongful fear. But how do the Scholastics argue that this sin of omission may be voluntary? Some claim that in every sin there is an inner illicit act or exterior command: interior, as to wanting to omit or wanting not to do what has been commanded, or wanting to suspend the act which one is bound to do, or wanting to do an act that is incompatible1 with an act (which cannot happen with an act at one and the same time) to which he is bound. Regarding the exterior, as the doing of something at the time when one is bound to do something else which keeps him from what he is bound to do.
On the contrary, some argue that the sin of omission does not require such a positive act, for not doing what has been commanded is a sin of omission, and their opinion conforms more with the truth. Thomas ([ST,] 1.2., q. 71, art. 5): “If in the sin of commission that alone which of itself has the nature of sin is meant, then at times the sin of omission occurs with an inner act and at times absent any act, whether interior or exterior. But if in the sin of omission the causes or occasions for omitting are also meant, then it is necessary for some act to be present in the sin of omission.”
Occam and Biel, who followed him (Sent., bk. 2, dist. 42), argue clumsily against Thomas and say: “No one sins in that which cannot be avoided. Rather, whoever is bound to do this or that could not avoid the omission, for on the basis of the hypothesis he does not think about it. Therefore he does not sin by omitting.” Thus they prefer the opinion of Alexander of Hales that the sin of omission is a positive inner act of the will—or at least does not exist without such an act. But Thomas responds to this argument very correctly through a limitation: “No one sins in that which he cannot avoid, that is, if he himself has not fallen into that impossibility from his own fault; otherwise the rule does not follow. It is as if someone were to hurl himself voluntarily into a pit out of which he could not climb.”
Are the sins of omission and of commission different in species?
§ 27. They ask in addition: “Do the sins of omission and commission differ in species?” We respond. Thomas ([ST,] 1.2., q. 72, art. 6):
Sins are distinguished both materially and formally. The material distinction of sin is observed in the natural species of the acts; the formal, in relation to its own end. If we are speaking materially of the species of sins of commission and omission, they differ in species; but if we are speaking formally about the species of the sins of commission and of omission, they do not so differ in species because they are destined for the same purpose and proceed from the same motive. The greedy man both robs and does not give what he ought to give, for negation is always based on some affirmation.
Those are the words of Thomas. The question can also be resolved in the following way. We can discuss sin in the concrete or in the abstract. Sin taken in the abstract denotes privation. Sin taken concretely indicates not only privation but also a supporting habit or action. On the basis of the first consideration, sins of omission and of commission do not differ, because in both cases there are lawlessness and privation. But in the latter consideration they certainly differ, for the one is an act in the sin of commission and the other in the sin of omission.
1 Read incompossibilem with Cotta instead of in compossibilem.