Q: Whether Backbiting Is the Gravest of All Sins Committed Against One's Neighbor?

A: On the contrary,
It is more grievous to sin by deed than by word. But backbiting is a sin of word, while adultery, murder, and theft are sins of deed. Therefore backbiting is not graver than the other sins committed against one's neighbor.

I answer that,
The essential gravity of sins committed against one's neighbor must be weighed by the injury they inflict on him, since it is thence that they derive their sinful nature. Now the greater the good taken away, the greater the injury. And while man's good is threefold, namely the good of his soul, the good of his body, and the good of external things; the good of the soul, which is the greatest of all, cannot be taken from him by another save as an occasional cause, for instance by an evil persuasion, which does not induce necessity. On the other hand the two latter goods, viz. of the body and of external things, can be taken away by violence. Since, however, the goods of the body excel the goods of external things, those sins which injure a man's body are more grievous than those which injure his external things. Consequently, among other sins committed against one's neighbor, murder is the most grievous, since it deprives man of the life which he already possesses: after this comes adultery, which is contrary to the right order of human generation, whereby man enters upon life. In the last place come external goods, among which a man's good name takes precedence of wealth because it is more akin to spiritual goods, wherefore it is written (Prov. 22:1): "A good name is better than great riches." Therefore backbiting according to its genus is a more grievous sin than theft, but is less grievous than murder or adultery. Nevertheless the order may differ by reason of aggravating or extenuating circumstances.

The accidental gravity of a sin is to be considered in relation to the sinner, who sins more grievously, if he sins deliberately than if he sins through weakness or carelessness. In this respect sins of word have a certain levity, in so far as they are apt to occur through a slip of the tongue, and without much forethought.

Reply Obj. 1: Those who detract Christ by hindering the faith of His members, disparage His Godhead, which is the foundation of our faith. Wherefore this is not simple backbiting but blasphemy.

Reply Obj. 2: Reviling is a more grievous sin than backbiting, in as much as it implies greater contempt of one's neighbor: even as robbery is a graver sin than theft, as stated above (Q. 66, A. 9). Yet reviling is not a more grievous sin than adultery. For the gravity of adultery is measured, not from its being a union of bodies, but from being a disorder in human generation. Moreover the reviler is not the sufficient cause of unfriendliness in another man, but is only the occasional cause of division among those who were united, in so far, to wit, as by declaring the evils of another, he for his own part severs that man from the friendship of other men, though they are not forced by his words to do so. Accordingly a backbiter is a murderer
occasionally,
since by his words he gives another man an occasion for hating or despising his neighbor. For this reason it is stated in the Epistle of Clement [*Ad Jacob. Ep. i] that "backbiters are murderers," i.e. occasionally; because "he that hateth his brother is a murderer" (1 John 3:15).

Reply Obj. 3: Anger seeks openly to be avenged, as the Philosopher states (Rhet. ii, 2): wherefore backbiting which takes place in secret, is not the daughter of anger, as reviling is, but rather of envy, which strives by any means to lessen one's neighbor's glory. Nor does it follow from this that backbiting is more grievous than reviling: since a lesser vice can give rise to a greater sin, just as anger gives birth to murder and blasphemy. For the origin of a sin depends on its inclination to an end, i.e. on the thing to which the sin turns, whereas the gravity of a sin depends on what it turns away from.

Reply Obj. 4: Since "a man rejoiceth in the sentence of his mouth" (Prov. 15:23), it follows that a backbiter more and more loves and believes what he says, and consequently more and more hates his neighbor, and thus his knowledge of the truth becomes less and less. This effect however may also result from other sins pertaining to hate of one's neighbor.