1149. The precept of love of enemies did not originate with the law of Christ. (a) It pertains to the natural law, for (i) it follows from the natural principle: “Do unto others as you would have them do unto you,” and (ii) it was known by natural reason (e.g., Plato and Cicero knew it). (b) Love of enemies was commanded in the Old Law, being the second great commandment of that law (Matt., xxii. 39), and was taught in various Old Testament books (Lev., xix. 17, 18; Exod., xxiii 4, 5; Prov., xxi. 21, 22). (c) It was renewed by Christ, who corrected the false interpretation of Leviticus, xix. 18, given by the scribes and Pharisees, who taught: “Thou shalt love thy friend and hate thy enemy.” In the Sermon on the Mount our Lord declares: “I say to you: Love your enemies: do good to them that hate you: that you may be the children of your Father who is in heaven” (Matt., v. 44, 45).
1150. The following examples of love of one’s enemies are found in the Bible: (a) in the Old Testament, Joseph forgave his brethren who had sold him into Egypt, David spared the life of his persecutor Saul and wept over the ungrateful Absalom, and Moses prayed for the people who had rebelled against him; (b) in the New Testament our Lord mourned over Jerusalem which had rejected Him, and on the Cross prayed for His enemies.
1151. What kind of love must we entertain for enemies?
(a) A general love of enemies is that which extends to all neighbors for the love of God, no exception being made as regards enemies. This kind of love is required. Example: Caius makes an act of love in which he declares his love for his neighbor, but mentions no names. Titus makes this act of love: “I love all except Caius.” The act of love made by Caius is sufficient, that of Titus is insufficient.
(b) A special love of enemies is that which extends to them in particular, not as included in the human race or the community, but as individuals, as when one expressly mentions the name of an enemy in his act of love. This kind of love of enemies is not required at all times.
1152. Is there an obligation of special love of enemies? (a) In cases of necessity (e.g., when the omission of a special love would bring on hate), one is bound to special love. (b) Outside of cases of necessity, one is bound to be willing to love an enemy in particular, if the necessity should arise. (c) Outside of necessity, one is not bound to love an enemy in particular, for it is impossible to give such attention even to all those who are not enemies. But to give an enemy more love than is required is a sign of perfect charity.
1153. The principles just given as to internal love of enemies apply also to external love, or to the signs by which internal love is manifested. For St. John says: “Let us not love in word, nor in tongue, but in deed, and in truth” (I John, iii. 18).
(a) Hence, it is not lawful to deny to an enemy the common signs of charity (i.e., such benefits as are bestowed on his community or class as a whole), for to do so would be to signify a desire for revenge (Lev., xix. 18). Consequently, he who excludes his enemies from prayers offered for his neighbor sins against charity.
(b) In cases of necessity, as when an enemy is in great need as to life, fame, fortune or salvation, one is bound to show special signs of charity, such as salutation, conversation, assistance, etc. Thus, we are told: “If thy enemy be hungry, give him to eat; if he be thirsty, give him to drink” (Prov., xxv. 21).
(c) Outside of cases of necessity, one is bound to be ready to assist an enemy, should there be need.