(a) Thus, one is bound to explicit love directly (or by reason of charity itself), when the law of charity requires this. _Per accidens_, charity requires an internal act of love, when without this act some good commanded by charity (e.g., reconciliation with an enemy, alms to one in distress) will not be done, or some evil forbidden by charity (e.g., hatred, revenge) will not be overcome. _Per se_, it does not seem that charity requires explicit acts of love towards the neighbor, but only those implicit acts contained in the love of God; in practice, however, conscientious persons frequently make explicit acts of fraternal charity, as when they pray for the living and the dead, or say the Our Father with due attention and devotion.
(b) One is bound to explicit love indirectly (or by reason of some other virtue than charity), when apart from such explicit love that other virtue cannot be exercised as commanded. Example: Balbus is often tempted to defraud Caius, and does not resist the temptation successfully, unless he puts himself into a charitable disposition towards Caius.
1604. The Necessity of Charity.—(a) The habit of charity is necessary as a means (see 360, 785) for all persons, infants included, so that without it no one can be saved. For it is only with this virtue that one possesses the divine indwelling (I John, iv. 16), and is made a friend of God. Those who have not the wedding garment of charity are cast into the outer darkness (Matt., xxii. 13).
(b) The act of charity is also necessary as a means of salvation to all adults, for it is only by actual charity that they turn towards their Last End, and without actual charity they are in death (I John, iii. 14). A person who is justified through attrition joined with a Sacrament receives grace and the habit of charity, and by his voluntary acceptance he consents to the divine friendship and thus makes an act of charity.
(c) The act of charity is obligatory under grave precept at the beginning of the moral life, frequently during life, and at the hour of death (see 1594 sqq.).
1605. Is it possible that a sin against the love of God be only venial? (a) The imperfection of the act makes such a sin only venial, as when without full deliberation one wishes to omit an obligatory act of love. (b) The slightness of the matter makes such a sin venial, when it is aside from, but not contrary to, the love of God, as when one makes an act of love of God with culpable lukewarmness. Venial sin is not, strictly speaking, opposed to the commandment of love, since it does not destroy love.
1606. As the order of charity is commanded as a part of the law of charity, one is obliged not only to love those to whom love is commanded, but also to give greater love to those to whom greater love is due.
(a) God must be loved above all creatures, since He is to be loved with the whole heart (Deut., vi. 5; Matt., x. 37).
(b) Self must be loved more than the neighbor, for love of neighbor is commanded only as like to that of self (Matt., xxii. 9).
(c) One should love one’s neighbor more than one’s own body, since we ought to lay down our lives for the brethren (I John, iii. 16). The claims of self and of the neighbor to love are in the following order: the spiritual goods of self, the spiritual goods of the neighbor, the bodily goods of self, the bodily goods of the neighbor, the external goods of self, the external goods of the neighbor.