Answer
I think to understand why God gave man the cultural mandate, it's important to remember that man was uniquely created in his own image. So there's a structural component to the divine image — we just are in God's image. But then there's also the functional component, that we show and display the glory of God in the particular way that's just right for us being human by the way that we carry out and reflect his glory through the work that we do. And so when we think about the cultural mandate, we have sort of a work to fill the earth and to subdue it, to make the world like Eden, like the Garden, and so on, but also to fill it, to populate it. And so the idea is that we are to carry out the cultural mandate to spread the glory of God displayed uniquely in his divine image in human form to the ends of the earth for his own glory.
Answer by Dr. Bruce Baugus
Dr. Bruce Baugus is Associate Professor of Philosophy and Theology at Reformed Theological Seminary in Jackson, Mississippi