The creed tells us that Jesus Christ, the only Son of God, is “eternally begotten of the Father, God from God, Light from Light, true God from true God, begotten, not made, of one Being with the Father.”

This theologically dense language was forged in the crucible of a controversy that is almost completely alien to the modern mind. The Greco-Roman world of late antiquity was a culture that cared passionately about ideas and could not have imagined our present timidity which keeps discussion of the most important things locked safely in the closet while obsessing over sports scores and whatever Paris Hilton is doing today.

The question that nearly tore the fourth-century Church apart was not a trivial one. In plain English, it was Jesus’ question, “Who do you say I am?” Peter’s answer — “You are the Christ, the Son of the Blessed” — has always been the faith of the Church.

Jesus had, after all, claimed to be God and had showed that he wasn’t kidding by rising from the dead. Yet, while he insisted he was God, he also did puzzling things, like praying to his “Father” in heaven, calling the Father God as well, and even saying, “The Father is greater than I.” This, combined with St. John’s very direct proclamation that Jesus was the Word who both was with God and was God, set the course for Christian worship of the Father, Son and Holy Spirit as God.

But clever theological minds can always find a way to introduce confusion.

Such a mind was Arius, who proposed, instead, that Jesus was a sort of godlet, not God with a capital “G.”

He preached that Jesus was sort of like a super archangel: greater than all other creatures (and so, “divine” in comparison with the rest of creation), but not actually God. This seems abstract, but it actually constituted an assault on the most fundamental basics of the Christian faith, because if Jesus is not God, he can neither save nor give eternal life (that is, the life of God) to us.

The Council of Nicaea, in resolving the controversy, insists (following St. John) that Christ is “begotten, not made.” Why? For the same reason we insist that our children are not the same as statues.

An artist makes a statue; he begets a son. To beget is to share your nature with another being. God made human beings. But God the Father begets the Son eternally. The Son shares his Father’s nature. And since the nature of the Father is to have no beginning, the Son also has no beginning. He is begotten from all eternity by the Father. In him is eternal life from the Father, and, therefore, he can share that life with us creatures.

For eternal life originates only in God, not in creatures.

The eternity of Christ is a stunning thing to contemplate: that this manual laborer who stands before us with dirty feet, calloused hands, and a rough up-country accent is, in fact, the Being who has existed from all eternity in the blinding light of the heart of God, sharing completely in his glory and showing forth the express image of the Holy One who hurled all the galaxies into being.

It is rather a lot to take in.

It’s no wonder the Son “emptied himself,” as Paul says, becoming human and dimming his splendor so that we could see him with our mortal eyes. And yet, even dimmed, he remains the Light of the world.

When you look at the sun, do you see the sun or the light from the sun? Obviously, to do the one is to do the other. Christianity says the same thing is happening when you look at Christ. If you’ve seen the Son, you’ve seen the Father, for the Son is the exact representation of the Father, just as sunlight carries with it the exact representation of the sun from which it came. That is why the creed calls Jesus “Light from Light.”

The doctrine of the Trinity is frequently despised by our post-Christian culture as the archetype of sterile philosophical disputation. But, in reality, the doctrine of the Trinity simply means God is love. Jesus revealed to his startled hearers that God was most deeply one in the way a family is one.

His oneness is not the oneness of lonely and awful isolation, but the oneness of Love. There exists within God the mystery of the family, of a Father who begets the Son in perfect self-donating love, of a Son who mirrors that love back to the Father in perfect adoration, and of a Holy Spirit who eternally proceeds from this mysterious union of Persons; yet, all the Persons are one God. It was to take us into that eternal dance of glory that the Son came.

Mark Shea is senior content editor

for CatholicExchange.com.