Here “human nature” does not stand for a type which can be defined. As a type or form human nature is a timeless abstraction which is in no place. What is in the type is there by definition. For this post, human nature is that in reality which are the humans – the human part of nature. Perhaps, “humanity would be a better term. If we think of the type or form of human nature, no definition of this type would imply that humans fight endless wars. Humans are not necessarily by definition warlike. So, being warlike is not in the type human nature. But in actuality humans are warlike. So, even if it is a contingent fact that we fight endless wars, we can say that being warlike is natural for humans.
Humanity does not have a fixed spatial location. Humans might leave planet earth. Humanity has a temporal location. Humanity began when God gave a species of hominids moral souls. In this connection see: Supernatural Origin of the Human Soul. Human nature as humanity will cease to be if the human beings become extinct.
Human nature is a complex reality which includes radically different levels of reality. There is, of course, the physical reality of individual living human beings. The bodies of humans have definite spatial locations at any time. Individual humans have thoughts and feelings which can be dated but which have only an imprecise spatial location as in the vicinity of the thinking and feeling body. There are the vast intermingled collective thoughts and, I say, feelings of human beings. Some of these collections can be given imprecise spatial and temporal locations. For instance, the religious beliefs of an isolated tribe may imprecisely be located where the tribe lives. But they cannot be located as in the vicinity of individuals as can the religious thoughts of those individuals.
But there are other thoughts and sentiments or the capacity for them which are common to all individuals and cultures. Here I would emphasize that the universal thoughts and sentiments as residing primarily in the cultures because they do not come into existence and pass away as does the thinking of feeling of individuals. The universal thoughts and feelings could be called reason. However, labelling them as reason is not to classify all of them as correct.
God’s placed His commands in the reason of this complex reality of humanity. How? God gave human beings the capacity to think and feel morally. The capacity to think morally is primarily the capacity to think that what is good is to be promoted and never directly inhibited. The capacity to feel morally is primarily the capacity to desire ends God has intended for humans. The divinely intended ends are the goods which ought to be promoted and never inhibited. Human beings use reason to articulate basic universal moral imperatives to the effect that the basic goods God intends are to be promoted and never inhibited. Moral thinking and feeling is the crucial part of humanity for uncovering and articulating these divine commands.
The articulation, which includes justifying the articulation, is a human achievement. However, man is not the measure of all things because God’s commanding is the intending of the ends for humans. Our uncovering and articulating is a response to what God intends.
Can we be absolutely certain that what has been articulated as God’s commands are indeed what God commands? When we actually provided a defense for an articulation of a moral command we can be very confident that we have “got it right.” However, when we raise this question about absolute certainty, in abstraction from considering any argument, we can only reply as in the case of getting it right about facts. We cannot know that we know.
But the whole moral order is not given by God. The whole moral order consists of basic moral laws which, as I just wrote, can be understood as response to what God intends. But rules on how to implement basic moral laws in particular circumstances can be understood as human constructions which very from place to place.
But there are other moral laws which are human constructions and are also universal. These are the moral laws requiring correction for violation of moral laws. They can be called laws of justice. In general they prescribe that some harm ought to be done. I once called these rules of justice ad hoc moral laws. See Making ad hoc moral laws. I need to elaborate much more on what I have just called the moral order. But the purpose of this post is only to specify the foundational part of this order as given by God.