1. Most ethical systems take it for granted that, except for those with whom one has a special relationship, one need only avoid harming others. But Christian responsibility extends to all humankind. “Neighbor” is not a predefined category but includes all who need redemption—in other words, all without qualification. A conscience formed by the demands of charity must therefore pursue the salvation of all, and this salvation includes their human fulfillment.
2. How, then, can a Christian rightly prefer certain persons? Of course, this question cannot be taken to ask how a Christian can rightly practice unfair discrimination. Nor should it be taken to ask how a Christian can rightly have a stronger attachment to some persons—for example, to friends and family. Rather, the question is how Christians can rightly have policies of preferring to benefit some persons rather than others by their good actions. For example, how does one justify the policy of preferring to do good to those who are of the household of the faith?
3. The answer essentially is that there is an order in charity, grounded in the Trinity. Among human persons, some are direct media of salvation for others. Priority of love among members of the Church is required by her mission, while individuals fulfill their general redemptive responsibility by fulfilling specific responsibilities to specific persons according to their personal vocations.
4. This can be explained as follows. Charity is a disposition toward fulfillment in divine life. Fulfillment in divine life is a communion of persons among whom there is a definite order; thus, there is an order in charity. No one comes to the Father except through the Son (see Jn 14.6); and, since Jesus loves his human brothers and sisters as the Father loves him (see Jn 15.9), it follows that the natural unity of the Father and the Son is the precondition of the communion of human persons in divine life. United in Jesus, not as isolated individuals, human beings share in divine life and become God’s children (see Jn 1.12; 17.20–26). The Spirit who pours forth charity (see Rom 5.5) is the Spirit of the Son (see Gal 4.6). Thus, in their relationships with each other and with us, the divine persons are not interchangeable.
5. There is likewise an order in charity among human beings (cf. S.t., 2–2, q. 26, aa. 6–8). All who are saved are saved by being united with Jesus as members of his Mystical Body, the Church (see Eph 2.11–22). But within the Church there are different roles and a definite order—for example, the apostles and prophets provide a foundation (see Eph 2.20). Thus, in their relationships with one another and with those outside the Church, human persons are not interchangeable.
6. The order inherent in charity explains why so much emphasis is placed upon fraternal charity among Christians. Jesus demands that his disciples love one another (see Jn 13.34). The First Epistle of John repeatedly stresses the love of believers for one another. Love among Christians has a certain priority over their love for others: “As we have opportunity, let us do good to all men, and especially to those who are of the household of faith” (Gal 6.10; cf. 1 Pt 2.17).
7. This priority is not partiality and discrimination. The love which Christians have for one another is the necessary precondition for the revelation and effective communication of divine love to others (see Jn 13.34–35). The priority of love within the Church is determined by the Church’s mission of service in the redemption of humankind. Only if divine love is present in the Church can the Church communicate divine love to the world. Moreover, the intensity of love within the Church conditions its effectiveness in its mission to the world, as the intensity of heat in a furnace conditions its effectiveness in heating a whole building.
8. Charity requires that all human goods be pursued in every upright way by some Christian or group of Christians, for by their lives Christians prepare the material of the heavenly kingdom (see GS 38–39). Most goods can be pursued effectively only by a limited group who mutually commit themselves to their pursuit. Hence, charity requires such commitments—for example, of this man and this woman to one another in marriage.
9. In making such commitments, one assumes definite responsibilities to definite persons. As part of one’s Christian life, all such commitments belong to one’s personal vocation. Charity requires Christians to carry out their personal vocations. Therefore, charity requires that Christians make a policy of preferring to benefit some persons rather than others by their good actions. Parents, for example, must raise their own children before going off to engage in missionary activity on behalf of people in a distant land. Even Jesus’ personal vocation included a special responsibility for Israel (see Mt 15.21–28).
Charity is community forming; love builds up the Church (see 1 Cor 8.1; Eph 4.15–16). This follows from the nature of charity as a communion of divine and human persons. For this reason, one ought not to think of Christian love individualistically, as if it were a bond only between individuals—individual souls and God, or any other pair as “I” and “thou.” The relationship of love begins with a single “I” in only one case: that of the Father from whom everything proceeds. In this case, it immediately unfolds into the “we” of the Father and the Son together, from whom as a single source the Spirit proceeds, and then by generous freedom into the “we” of the creator who says: Let us . . ..
In loving with charity, then, one always loves as part of a fellowship and loves many persons in communion. As a member of the Church carrying out her apostolic mission to the world, one loves unbelieving humankind. As part of his created family loving its source, one loves God. This characteristic of charity solves the problem, often raised, of how love can be universal without being diluted to such an extent that it becomes a mere abstract philanthropy, like that of secular humanists who love humankind in general but are willing to sacrifice certain individuals. By Christian charity, one’s love, on whatever scale, is engaged in a real and cooperative work. The larger the scale of this work, the greater the demand for charity in deed and in truth among those who share in the more immediate relationships necessary to carry it out.