Because God reveals himself in the language of love, we must reflect on human love to understand the love which God is and which he calls us to share. Love, basically a disposition to a known good, is of two fundamentally different kinds: in respect to sensible goods, an emotion; in respect to intelligible goods, rational concern or caring. While love is always first of all a disposition to the fulfillment of the one who loves, it is not limited to caring about one’s own good. Insofar as goods to which one is disposed by love are actualized in other persons, one loves them. Emotional love is affection focused upon another with whom one identifies in some way. Volitional love of another person is a disposition established by commitment to a common fulfillment. Mutual volitional love disposes those who share in it to a simultaneous increase in both individual perfection and communion.
God is a unity of three distinct persons. The ideal of love, unity and multiplicity at their ultimate, is best realized in God. The mystery of the Trinity, in which the one and the many are absolutely reconciled, is a mystery of love, specifically a mystery of the communicability of divinity. Since God’s very constitution is love, sharing in his love means sharing in his life. It is not true either that human beings must always remain extrinsic to God or that their communion with him means being absorbed into God; instead, the mystery of the Trinity shows both that divine life is not in principle incommunicable and that loss of individual selfhood is not necessarily the price of its communication.
God’s love makes us his adopted children, called to share intimately and fully in his life; the Spirit is the principle of this adoption. Although the natural sonship of our Lord and our status as adopted sons and daughters are distinct, the communion Jesus intends for his disciples is nevertheless based on a strict analogy with his Father’s love for him: Jesus wants it known that the Father loves his followers as the Father loves him. To abide in God’s love is to be drawn within the communion of God. In this situation human persons, though always remaining human, really share in divinity. While it may seem strange to speak of the divinization of human beings, the Fathers of the Church do not hesitate to speak in this way.
The act of living faith is the principle of our sharing in the divine nature. We are justified by faith in Jesus—justified, as Trent teaches, by a rightness which is not merely attributed to us but which we receive as our own: God’s love is poured forth into our hearts and remains in them. Living faith is wholly God’s gift to us, but it is also our own human act. Initially, seeing the credibility of the gospel, we choose to believe for the sake of some human good; but having done so, we receive the gift of God’s love, and our choice is transformed, becoming an act of living faith made for love of God. This is how a person enters freely, by human choice, into intimate communion with God.
Formerly, much popular Christian piety suggested that loving God meant preferring him to created goods, but this is not the teaching of Vatican II. God’s love is all-inclusive; the love of God given us by the Spirit is a share in God’s love. Our supernatural love is therefore all-inclusive as God’s love is, embracing all genuine human goods. In loving himself, God loves creatures, whose goodness becomes real by his creative choice. Since God loves human persons, he loves the goods which fulfill them; to love as God loves, therefore, we also must love the goods which fulfill us humanly.
In morally good choices, we act toward human goods in a way compatible with God’s all-embracing love of them. In a morally evil choice, a sin, we act in a way incompatible with a will toward integral human fulfillment. Because every immoral act disrupts communion with God, one must say that in sinning one prefers a limited, human good to the love of God—but not as if love of divine goodness and love of human goods were incompatible or were alternatives for choice.
In Christian life, as in the life of Jesus, the human and divine are distinct but not opposed, united but not commingled. Commingling of grace and nature makes it impossible to delineate the likeness of Christian life to the life of Jesus, makes holiness appear a kind of dehumanization, destroys the autonomy of the natural order, and reduces the Christian’s share in divine life to a mere metaphor. At the same time, the make up of the Christian is not that of Jesus. In him the union of the divine and human is hypostatic—a union in his unique, divine personhood—while in us divine life is a dynamic principle, a principle of free choices and the life which flows from them. This account is essential for understanding Christian moral principles; it safeguards the integrity of human goods, precluding any supposed need to downgrade or deny the human for the sake of the divine, and preserves the validity of the natural law.