What does Psalm 8:6 mean?

When God created Adam and Eve, He crowned them to be co–regents with him over creation (Genesis 1:26–27). He told them to "Be fruitful and multiply and fill the earth and subdue it, and have dominion over the fish of the sea and over the birds of the heavens and over every living thing that moves on the earth" (Genesis 1:28). However, Adam and Eve failed to carry out this assignment. They yielded to temptation and sinned against the Creator (Genesis 3:6–7).

It remains for the last Adam, the Lord Jesus Christ, to bring the earth under His control (1 Corinthians 15:45–47). He will do this upon His return to earth. Isaiah 9:6–7 prophesies about Jesus' reign on earth by stating: "For to us a child is born, to us a son is given; and the government shall be upon his shoulder…Of the increase of his government and of peace there will be no end, on the throne of David and over his kingdom, to establish and to uphold it." First Corinthians 15:27 states, "For 'God has put all things in subjection under his [Jesus'] feet.'"