God gave humanity the cultural mandate in the most simple terms so that the world, the creation would be filled with his glory. We see a picture of creation as being something like the construction of a house, sort of like an ancient temple. And when a temple is built, the god who commissioned its building inhabits it. And so, the biblical view of creation is that the whole earth was made to be a dwelling place for God, to be a holy sanctuary. But instead of a statue representing God — a statue of a bird or a lion or something like that — being placed in that temple, God placed man and woman as his image bearers. And in giving the cultural mandate, God was in effect saying, "Go multiply my image, fill the earth, and then bring it under dominion, exercise authority over it like it a priest." And so, the cultural mandate was so that God's image bearers would go exercise God's lordship over the created world so that the earth would be a dwelling place for the God who made it, just like his heavenly throne room, glimpses of which we see in places like Isaiah 6, the earth was to be the same. And so it's not a new thing for, for instance, the Old Testament to tell us that the earth will be full of the glory of the Lord as the waters cover the sea, because that was God's original design for it. And in the book of Revelation we see this. We see there's no temple in the new heavens and new earth, and there's no sun or moon because the Lamb and God are its temple, and the glory of God is the light of creation day and night. And so, while it was originally to be accomplished through the cultural mandate of man and woman being fruitful and multiplying and filling the earth and subduing it, God, in spite of the Fall, fulfills that mandate by Christ as the second Adam and by his obedience and by his gathering to himself a people who will be faithful to multiply and fill the earth under the Great Commission.