The explanation in question E undermines two common objections launched from different theological perspectives against Catholic teaching concerning natural law. Some Catholic theologians have suggested that natural law is more or less irrelevant, since human persons never exist in a state of pure nature. Many Protestant theologians argue that natural law is no longer relevant and trustworthy, because fallen humankind which follows nature merely conforms to its own corruption. The answer in both cases is that in our Lord Jesus human nature is found as it should be; the law present in every human heart is fulfilled in him in an exemplary way. The theological articulation of moral norms and virtues provided in chapter twenty-six will be based upon him, not upon any abstract pure nature nor upon nature as we find it in ourselves and in sinful humankind generally.

Still, one should distinguish between human nature understood as that which is actually given (even in Jesus) and human nature understood as that fulfillment of which human persons are radically capable. If one takes the former, static concept of nature as normative, one either must reject natural law or develop an unacceptable theory (4‑F). When it is admitted that the human nature which is given differs in diverse historical conditions, the conclusion inevitably follows that human nature—and so any morality based upon it—changes.¹⁸ However, if one takes the latter concept of nature as normative and articulates it by a description of the various basic categories of human goodness, then one can develop a dynamic theory of natural law, by which one can account both for the continuity and the legitimate unfolding of human moral insight.

Despite this distinction, which takes us some way toward answering objections against Catholic moral teaching insofar as it articulates the requirements of natural law, the human condition subsequent to the fall does obscure the real possibilities of human persons. Moreover, the changes which occur in conventional morality as one moves through diverse times and places, humanly organized as diverse cultural units, raise doubts as to what is the real core of human possibility.

The concretization of the norm of Christian morality in the character of Jesus provides a remedy for these difficulties. In him, human persons see what a man can be. His good life is not rendered ambiguous by mixed motives; his human commitments are not limited by compromises with sin. The possibilities of human nature, which are known naturally (up to a point and with more or less mixture of error), are revealed in Jesus and become accessible to every man and woman by faith which accepts him in his total, Incarnate reality.¹⁹

Moreover, Jesus is not a mere historical figure out of the past. He remains—the same yesterday, today, and forever—a standard by which to reject false teaching (see Heb 13.7–9). This remaining is real because Christian life is not merely an independent life modeled upon his, but is a real, communal sharing in the central action of his life. This point was explained in chapter twenty-three.

The Stoic philosophers, who so strongly shaped the more noble secular moral standards of Greco-Roman culture at the beginning of Christianity, articulated a moral ideal in terms of the cardinal virtues of wisdom, justice, temperance, and fortitude. St. Paul confidently asserts the autonomy of the culture centered upon Jesus, whose death and resurrection struck the “wise” as foolish. God “is the source of your life in Christ Jesus, whom God made our wisdom, our righteousness and sanctification and redemption” (1 Cor 1.30).

Human culture is rooted in the basic human goods, and any culture more or less adequately serves them (see GS 53). In Jesus, the Word of God enters into history as the perfect man and reorganizes the wreckage of human community into a culture worthy of human dignity (see GS 38). Christian holiness, therefore, conforms to human nature (see LG 40). Yet, in Jesus human morality also is renewed and transformed. Wisdom and justice (righteousness) take on a new depth and meaning. Self-control yields to sanctification and fortitude to redemption, as limited goods are embraced by the prospect of glory and human evils are overcome by the might of God’s intervention. Stoicism has long since died out with the classical culture to which it belonged; Jesus’ way to a renewed humankind remains.