A wide variety of views on the relation between the Christian faith and moral decision has been held by Christians, and this is reflected in important differences over concrete issues such as war, race, and social morality, and on its relationship to other major religions and philosophical views. These differences emerge early in the history of the church with the Augustinian emphasis on the need for renewal of the human will and the search for God as man's chief good, rather than on detailed duties (e.g., Didache). Perfect moral freedom is to be found in obedience to God. Similarly in Reformation theology and again in Neoorthodox theology, moral obligations arise out of a direct encounter with God and depend on His sovereign will. Moral problems are a matter of the will, not the intellect; hence the need for the regenerative power of God to enable one to do what is right. Luther sees God as giving the believer freedom-to serve so that the Christian is both “subject to none and subject to all.” Calvin stressed the subjection of the Christian to the law and the Gospel, though for the unbeliever the law is a reminder of his inability to fulfill God's commands and may therefore lead him to repentance.
Puritanism is indebted to Calvin for its sense of divine sovereignty and, with the teaching on the civil magistrate, attempted to place the whole of society under God's law, though there were differences, e.g., about the degree of religious toleration. Greater emphasis was placed on the Bible as defining specific unchangeable duties to God and the neighbor, and to these many Puritans added further detailed instructions. Examples of this Reformed tradition are found today in the work ofand Carl F.H. Henry.
Neoorthodox theology shares with the Augustinian tradition the view that of ourselves we cannot know the good, the will of God. This is known only through revelation, not to be identified with the Bible. The command to love God and one's neighbor does not vary in intention, but in content according to the conditions with which it deals. Ethics is essentially a matter of free decision, and it is not possible to know beforehand what the requirements of God are for any situation. This is the interpretation of the Christian ethic to be found in the work of H.E. Brunner*; the same motif appears in Bonhoeffer's* call for discipleship, and in Bultmann's* call to “radical obedience.” This view has led to the development and popularization of “situation ethics” and koinonia ethics.
The Roman Catholic approach to ethics depends on the notion of natural law. Morality is “natural” in the sense that it has its source in rational reflection on the true “end” of human life. The pluralism of modern Western civilization makes this implausible. The extent to which the church is thought necessary to enable people to discern their duty has varied. Theologians such as Karl Rahner have tried to modify the rigidities (as they see it) of the classic natural law position by stressing (in Neoorthodox fashion) the importance of the individual and the concrete. Debates on birth control and abortion show the extent to which the traditional position has been eroded by secular utilitarian morality, or by truly biblical insights, or “situationalism.”