Now a man wishes a thing in three ways: first, by his natural appetite; thus all men naturally wish to be and to live: secondly, a man wishes a thing from deliberate choice: thirdly, a man wishes a thing, not in itself, but in its cause, thus, if a man wishes to eat what is bad for him, we say that, in a way, he wishes to be ill.
Accordingly the motive of mercy, being something pertaining to misery, is, in the first way, anything contrary to the will's natural appetite, namely corruptive or distressing evils, the contrary of which man desires naturally, wherefore the Philosopher says (Rhet. ii, 8) that "pity is sorrow for a visible evil, whether corruptive or distressing." Secondly, such like evils are yet more provocative of pity if they are contrary to deliberate choice, wherefore the Philosopher says (Rhet. ii, 8) that evil excites our pity "when it is the result of an accident, as when something turns out ill, whereas we hoped well of it." Thirdly, they cause yet greater pity, if they are entirely contrary to the will, as when evil befalls a man who has always striven to do well: wherefore the Philosopher says (Rhet. ii, 8) that "we pity most the distress of one who suffers undeservedly."
Reply Obj. 1: It is essential to fault that it be voluntary; and in this respect it deserves punishment rather than mercy. Since, however, fault may be, in a way, a punishment, through having something connected with it that is against the sinner's will, it may, in this respect, call for mercy. It is in this sense that we pity and commiserate sinners. Thus Gregory says in a homily (Hom. in Evang. xxxiv) that "true godliness is not disdainful but compassionate," and again it is written (Matt. 9:36) that Jesus "seeing the multitudes, had compassion on them: because they were distressed, and lying like sheep that have no shepherd."
Reply Obj. 2: Since pity is sympathy for another's distress, it is directed, properly speaking, towards another, and not to oneself, except figuratively, like justice, according as a man is considered to have various parts (Ethic. v, 11). Thus it is written (Ecclus. 30:24): "Have pity on thy own soul, pleasing God" [*Cf. Q. 106, A. 3, ad 1].
Accordingly just as, properly speaking, a man does not pity himself, but suffers in himself, as when we suffer cruel treatment in ourselves, so too, in the case of those who are so closely united to us, as to be part of ourselves, such as our children or our parents, we do not pity their distress, but suffer as for our own sores; in which sense the Philosopher says that "harshness drives pity away."
Reply Obj. 3: Just as pleasure results from hope and memory of good things, so does sorrow arise from the prospect or the recollection of evil things; though not so keenly as when they are present to the senses. Hence the signs of evil move us to pity, in so far as they represent as present, the evil that excites our pity. _______________________
SECOND ARTICLE [II-II, Q. 30, Art. 2]
Whether the Reason for Taking Pity Is a Defect in the Person Who Pities?
Objection 1: It would seem that the reason for taking pity is not a defect in the person who takes pity. For it is proper to God to be merciful, wherefore it is written (Ps. 144:9): "His tender mercies are over all His works." But there is no defect in God. Therefore a defect cannot be the reason for taking pity.
Obj. 2: Further, if a defect is the reason for taking pity, those in whom there is most defect, must needs take most pity. But this is false: for the Philosopher says (Rhet. ii, 8) that "those who are in a desperate state are pitiless." Therefore it seems that the reason for taking pity is not a defect in the person who pities.