Personal Ethics. If one is a Christian who speaks and writes about ethics, it seems right and proper for one to disclose this at the outset so that, at the very least, others can be more alert to one's possible distortions of the evidence.
Descriptive Ethics. Christians of all kinds share several convictions about the nature of human life which make a difference. One of these is that human beings are bearers of the "Image of God" and for this reason they deserve to be treated with respect. Another is that the debate about the priority of either "self-interest" or "other regard" is misplaced because human lives are so interwoven that it is difficult to separate them. A third is that healthy adult human beings in normal circumstances possesses enough moral freedom to be held accountable for the choices they make. A fourth is that the human history is not entirely cyclical. A fifth is that evil,when this is understood as pain and suffering which are not outweighed by their benefits to those who experience them, is not an inevitable part of human life. This cluster of convictions, and others like them, describe human beings in ways which are distinctive enough to require Christians to be explicit about them.
Normative Ethics. Christians value some things more and experiences more highly than do others. Their lists of virtues and vices are not universally accepted. Their visions of human life at its very best and very worse are not those of everyone else. It is not possible to determine which of these values, virtues and visions is better than others without presupposing something else which is more basic. If we agree that long and comfortable human lives are generally better than those which are short and uncomfortable, we can begin to assess them by this criteria. They otherwise remain diverse.
Christians disagree about normative theories such as Divine Command, Natural Law, Utilitarianism and Kantianism. This is partly because the Old Testament and New Testament include omens of all of them.
Metaethics. Because they believe in one God in whom, by whom and to whom all human beings relate even when they do not realize it, Christians are not thoroughgoing ethical relativists who hold that all beliefs and practices can be assessed only by the ethical resources of the different societies from they emerge. They take special note of the degree of "overlapping ethical consensus" there seems to be.
Some Christian begin with generally shared convictions and reason step-by-step to specifically Christian ones. Other Christians reason in the opposite direction. They begin with specifically Christian convictions and reason step-by-step to ones that should be generally shared. It matters little whether one begins with the general or the specific providing one eventually reaches the other.
These four considerations justify talking about "Buddhist" ethics, "Marxist ethics," "Humanistic" ethics and so forth too. Every serious account of the moral life has to make its own choices in the areas of descriptive ethics, normative ethics and metaethics. Also, as a matter of personal ethics, those who speak and write about these things should be forthcoming about these choices.