…human beings enjoy a dignity and value that no other creatures possess. Too often we have arrogantly distorted this uniqueness into an unbridled license to trample and destroy the rest of creation. Actually, the biblical text explicitly commands people to “work it and take care of” the rest of creation (Gen. 2:15 NIV). But the truth remains–and it is fundamental to the whole project of civilization–that human beings possess a unique dignity and worth.
But what exactly does it mean to be created in the image of God? There have been two major ways that Christians through the ages have understood the imago Dei: a substantial and a relational understanding. Those in the substantial tradition (e.g. Thomas Aquinas) identify some essential capacity or faculty (e.g., our reason that makes rational thought possible or our will that enables us to choose freely) that distinguishes persons sharply from the rest of creation. People in this tradition tend to put less emphasis on the way that the fall has damaged the imago Dei in sinful persons.
Those in the relational tradition (e.g. Luther, Calvin, Karl Barth) understand the imago Dei by analogy with a mirror that reflects some object. The imago Dei, then, is not something inherent in persons, but rather the imago Dei is the relationship with God, which exists when one obeys God. Through one’s right relationship with God, one truly reflects God’s will and thus bears God’s image. In this view, sin largely or completely destroys the imago Dei in fallen people.
Ronald Sider, The Scandal of Evangelical Politics, 52-53