St. Irenaeus, from the Office of Readings for Wednesday of the First Week in Ordinary Time.
Through creation itself the Word reveals God the Creator. Through the world he reveals the Lord who made the world. Through all that is fashioned he reveals the craftsman who fashioned it all. Through the Son the Word reveals the Father who begot him as Son. All speak of these things in the same language, but they do not believe them in the same way. Through the law and the prophets the Word revealed himself and his Father in the same way, and though all the people equally heard the message not all equally believed it. Through the Word, made visible and palpable, the Father was revealed, though not all equally believed in him. But all saw the Father in the Son, for the Father of the Son cannot be seen, but the Son of the Father can be seen.
The Son performs everything as a ministry to the Father, from beginning to end, and without the Son no one can know God. The way to know the Father is the Son. Knowledge of the Son is in the Father, and is revealed through the Son. For this reason the Lord said:No one knows the Son except the Father; and no one knows the Father except the Son, and those to whom the Son has revealed him.The word “revealed” refers not only to the future — as though the Word began to reveal the Father only when he was born of Mary; it refers equally to all time. From the beginning the Son is present to creation, reveals the Father to all, to those the Father chooses, when the Father chooses, and as the Father chooses. So, there is in all and through all one God the Father, one Word and Son, and one Spirit, and one salvation for all who believe in him.
I am continually finding things in the Office of Readings that surprise and delight me. I had never thought before about the fact that the revelation of the Father by the Son did not begin with His incarnation, but was His mission from the beginning of time. This explains so well the fact that early man understood some of the truth of who God is just from observing His creation. It wasn't just that God's works reflected His glory, it's that they were created to actively reveal His glory.