A Philosophy Formed on Self Leads to an Ethic of Self

More on anthropocentrism from Stanley J. Grenz, writing in The Moral Quest:

"The philosophical approach begins and ends with the human person, the self...
By beginning and ending with the self, the enterprise of philosophical ethics seeks to assist the self in becoming 'better.' To this end general ethics explores what it means to be 'good,' and applied ethics, in turn, seeks to assist us in fulfilling the universal human goal of becoming a good person.
The Christian ethic, however, departs radically from this focus on the self with its attendant agenda of making human beings 'good.' By its very nature Christian ethics must begin and end with God. It finds both the basis and the goal of ethical living in God. Christian ethical reflection draws from a biblical understanding of what God is like and what God's purposes are. Hence its concern is the discovery of the divine will. The purpose of such deliberation is to advance the ways of God in the world, so that God may thereby be glorified."

Grenz is making the point that "the human moral quest erroneously begins and ends with the human person" (emphasis mine).

And here is the reason it is erroneous:

"Every anthropocentric ethic suffers from the loss of a transcendent reference point from which to derive its conception of the ethical life. Indeed, for its understanding of the good no general ethic can appeal beyond the human realm...Nor can any such ethic draw from anything higher than the specifically human for the meaning of ethical concepts such as love or justice. Thus if we operate within the confines of general ethics, our court of appeal can rise no higher than the human person or human society for the content of ethical ideals, including what it means to act justly or even to love one's neighbor."

Contrast that human-centered approach to the Christian approach:

"In the Christian ethic, in contrast, the human does not serve as the ideal point of reference. On the contrary the ultimate court of appeal for the ethical life lies beyond the human. It is nothing less than the divine nature as embodied in the narrative of God's actions toward humankind. As a result central ethical concepts such as justice and love find their definition from the biblical story of God acting in human history, which reveals God's own character."