This is an important question today, just as it was in the 5th Century. I dare say, we should consider both halves of this question separately to really understand the depth of Saint Peter's challenge. "Creation" can be viewed by women and men of faith as poetically narrated in Genesis, (chapter 1 and chapter 2), as authentic Truth from God, but is generally not viewed as "facts" by Scripture scholars. In contrast, women and men of science continue to search for the specifics of how the world began, such as the Big Bang theory. In both scenarios, most people consider the creation of the world in general terms; planet Earth is for all humanity, just as the separation of the light from the darkness is for all humanity. In practice, some thousands (or billions) of years after God's creation began to unfold, the sun does shine, and the rain does fall, equally on the good and the bad (Matthew 5:45).
But we need to consider Creation differently, more personally. When God created the earth, and the streams, and the clouds and the stars and gravity and black holes and the fish and the birds, He created them for you and me - individually, uniquely, by name. Jeremiah 1:5 tells us that before we were born, before we were cells knit together in our mother's womb, we were already sacred to God; sacred as unique individuals. God didn't just know Jeremiah before his call as a prophet, before his birth as a person some 600 years before Jesus birth; God knows you and me, and knew us before time as we know it began, too.
That means that each of us are intentionally part of the actual creation story, the divinely-inspired story recorded in the Bible. The author of Genesis did not know your name and my name, but God's creation has unfolded for you and for me as individuals known by God before time could be measured by sun rises and seasons. We were created by God out of His love for us, and all that we experience and encounter in "creation," in the world around us, is intentional. Yes, through our exercise of God's gift of free will mankind has distorted creation in thousands of ways, but that takes nothing away from God's creation of all we take for granted as the goodness and greatness of His love for us - for each one of us, as individuals made in His image.
Saint Peter Chrysologus emphasized this in the next part of his sermon: "Was not this entire visible universe made for your dwelling? It was for you that the light dispelled the overshadowing gloom; for your sake was the night regulated and the day measured, and for you were the heavens embellished with the varying brilliance of the sun, the moon and the stars." He continues, "...the Creator still works to devise things that can add to your glory. He has made you in His image that you might in your person make the invisible Creator present on earth; He has made you His legate, so that the vast empire of the world might have the Lord's representative."
Which is exactly why the second half of St. Peter's question is important for each of us to consider today: "Why was I made?"
God is not done with you or me yet; He has a purpose in mind for us. What will unfold before each of us in our lives manifests God's dream for you, and for me. You and I, we are the Lord's representatives in creation today. Let us pray for each other that we have the courage to discover His will, and to be faithful representatives of His truth and love in the world.