There is a hierarchy to everything.
1 Next, it is plain that neither all good works, nor all sins, are equal. Indeed, counsel is given only in regard to the better good. Now, counsels are given in the divine law concerning poverty, continence, and other like things, as we said above. So, these are better than the practice of matrimony and the possession of temporal things, but it is possible to act virtuously according to these latter, provided the order of reason be observed, as we showed above. Therefore, not all acts of the virtues are equal.
2 Again, acts get their species from their objects. So, the better the object is, the more virtuous the act will be in its species. Now, the end is better than the means to the end; and of the means, the closer one is to the end, the better it is. Hence, among human acts, that one is best which is directed immediately to the ultimate end, namely, God. After that, an act is better in its species the closer its object is to God.
Notes But, of course, the ends never justify evil means.
3 Besides, the good in human acts is dependent on their being regulated by reason. But it happens that some acts come nearer to reason than others. The more definitely these acts pertain to reason itself, the more they share in the good of reason, in comparison with the acts of the lower powers which reason commands. Therefore, there are some human acts that are better than others.
4 Moreover, the precepts of the law are best fulfilled as a result of love, as we said above. But it happens that one man does what is prescribed for him to do with greater love than another man. So, one virtuous act will be better than another.
5 Furthermore, while man’s acts are rendered good as a result of virtue, it is possible for the same virtue to be more intensified in one man than in another. So, one human act must be better than another.
Notes Once again, there is no Equality in life.
6 Again, if human acts are made good by the virtues, then that act must be better which belongs to the better virtue. But it is possible for one virtue to be better than another; for instance, magnificence than liberality, and magnanimity than moderation. So, one human act will be better than another.
7 Hence, it is said, 1 Cor. (7:38): “He who gives his virgins in marriage does well: and he does not give them does better.”
8 Moreover, it is apparent for the same reason that not all sins are equal, since one gets farther away from the end through one sin than through another, and the order of reason may be more perverted, and more harm may be done one’s neighbor.
9 Hence, it is said, in Ezekiel (16:47): “You have done almost more wicked things than they in all your ways.”
10 Now, by this consideration we refute the error of those who say that all meritorious acts and all sins are equal.
11 As a matter of fact, the view that all virtuous acts are equal seems to have a certain reasonableness, since every act is virtuous as a result of the goodness of its end. Hence, if there is some end of goodness for all good acts, then all must be equally good.
12 However, although there is but one ultimate end for the good, the acts that derive their goodness from it receive different degrees of goodness. For, there is in the goods that are ordered to the ultimate end a difference of degree, in so far as some are better and nearer to the ultimate end than others. Hence, there will be degrees of goodness both in the will and in its acts, depending on the diversity of goods in which the will and its act terminate, even though the ultimate end be the same.
13 Similarly, also, the notion that all sins are equal seems to have some reasonableness, since sin occurs in human acts solely because a person overlooks the rule of reason. But a man who departs a little from reason overlooks its rule, just as one who misses it by a wide margin. So, it would seem that a sin is equal whether the wrong done was small or great.
14 Now, support for this argument seems to come from the practice in human courts of law. In fact, if a boundary line is set up which a certain man is not to cross, it makes no difference to the judge whether he trespassed for a large distance or a small one; just as it is unimportant, when a fighter goes over the ropes, whether he goes very far. So, in the case of a man overstepping the rule of reason, it makes no difference whether he bypasses it a little or a great deal.
Notes John L Sullivan would agree!
15 However, if one takes a more careful look at it, in all matters in which the perfect and the good consists in some sort of commensuration, the greater the departure from the proper measurement, the worse will it be.
Thus, health consists in a properly measured amount of humors, and beauty in a due proportion of bodily members, while truth lies in a measured relation of the understanding, or of speech, to the thing. Now, clearly, the more inequality there is in the humors, the greater the sickness; and the greater the disorder in the members of the body, the greater is the ugliness; and the farther one departs from the truth, the greater is the falsity.
For instance, the man who thinks that three is five is not as wrong as the one who thinks three is a hundred. Now, the good pertaining to virtue consists in a certain commensuration, for there is a mean that is set up between opposed vices according to a proper judgment of the limiting circumstances. Therefore, the more it departs from this harmonious balance, the greater the evil is.
16 Moreover, it is not the same thing to transgress virtue and to trespass over boundaries set up by a judge. Virtue is, in fact, good in itself, and so to depart from virtue is an evil in itself. Hence, to go farther away from virtue is a greater evil. But to pass over a boundary line set up by a judge is not essentially evil, but accidentally so—to the extent, that is, that it is prohibited.
But in the case of events that are accidental, it is not necessary that “if one event taken without qualification follows another event without qualification, then an increase in the first event is followed by an increase in the second.”
This only follows in things which exist of themselves. For instance, it does not follow that, if a white man is musical, then a whiter man will be more musical, but it does follow that, if a white thing is a distinctive object of sight, a whiter thing is a more distinctive object for sight.
17 Yet there is this point to be noted regarding the differences among sins: that one kind is mortal and another venial.
Now, the mortal is that which deprives the soul of spiritual life. The meaning of this life may be taken from two points in the comparison with natural life. In fact, a body is naturally alive because it is united to a soul which is the source of life for it. Moreover, a body that is made alive by a soul moves by itself, but a dead body either remains without movement or is only moved from outside.
So, too, the will of man, when united by a right intention to its ultimate end, which is its object and, in a sense, its form, is also enlivened. And when it adheres to God and neighbor through love, it moves from an interior principle to do the right things. But when the intention and love of the ultimate end are removed, the soul becomes, as it were, dead, since it does not move of itself to do right actions, but either entirely ceases to do them or is led to do them solely by something external, namely, the fear of punishments.
So, whatever sins are opposed to the intending and loving of the ultimate end are mortal. But, if a man is properly disposed in regard to them, yet falls somewhat short of the right order of reason, his sin will not be mortal but venial.
Notes “The last act is the greatest treason. To do the right deed for the wrong reason.”