From Jason Dulle‘s blog:
“So God created man in his own image… And God said to them, ‘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 1:27a, 28)
“And Jesus came and said to them, ‘All authority in heaven and on earth has been given to me. 19 Go therefore and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit, 20 teaching them to observe all that I have commanded you. And behold, I am with you always, to the end of the age.’” (Matthew 28:18-20)
In the beginning of creation, God commissioned humanity to multiply themselves in number (through sex), and fill the earth. Similarly, in the beginning of the new age of the Spirit, Jesus commissions the disciples to multiply themselves in number (through evangelism and discipleship) throughout the earth. Whereas the first commission was aimed at proliferating human life globally, the new commission was aimed at proliferating eternal life globally. The sons of Adam had filled the earth, but a new commission was needed to fill the earth with the sons of God.