“For to us a child is born, to us a son is given; and the government shall be upon his shoulder, and his name shall be called Wonderful Counselor, Mighty God, Everlasting Father, Prince of Peace. 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 it and uphold it with justice and with righteousness from this time forth and forever more. The zeal of the Lord of host will do this.” (Is. 9:6-7)
This is a wonderful passage that is often read at Christmas time. It describes in exalted terms the Messiah who will come to Israel to save and judge and rule. But a question has always arisen in my mind about one of the names given to this “child” and this “son.” The prophet calls him “Everlasting Father.” How is it that the term Father is being applied to the Christ child? How can Jesus the Son be called “Father” without sliding into modalism of some form?
Modalism is a heresy that first emerged in the ancient church and had a faulty understanding of the Trinity. The Scriptures teach that God always exists in three equal persons. Modalism, although there are different forms, essentially believes that God always exists as one person who slides in and out of different modes. One moment God is the Father, another moment he is the Son, and then another moment he is the Spirit. So in this sense, the modalist would say that the Son merely transitions into the form of the Father.
So what about Isaiah 9? If the interpretation of modalism is wrong, how should we understand this passage? One person suggested to me after a Sunday School class that maybe Christ is called Father in terms of a parallel with Adam. Just as Adam is a father since he is the God-appointed head of humanity in creation, so Christ is possibly viewed as Father since he is the God-appointed head of a new humanity (Rom. 5; 1 Cor. 15). I think this suggestion has some merit in the fact that Scripture sees both Christ and Adam are covenantal heads of humanity. But this doesn’t seem to do much to alleviate the inter-trinitarian tension. I think there is still a better answer.
While reading Tertullian recently I was pointed to what seems like a better solution. Could the answer be found in the fact that Jesus himself claimed that “I have manifested your name to these men” (John 17:6). As Tertullian points out, in this sense it can truly be said of Jesus, “Blessed is he who comes in the name of the LORD” (Ps. cxviii.26), knowing that Jesus said, “I am come in my Father’s name” (John 5:43). This means that the prophet Isaiah generally applies the term Father to Jesus in light of his role of revealing the Father. As John says:
“No one has ever seen God; the only God, who is at the Father’s side, he has made him known.” (John 1:18).
In this sense, Jesus could say to Philip, ‘Whoever has seen me, has seen the Father’ (John 14:9).
This, admittedly, doesn’t remove all difficulty in our understanding of either the Trinity or this verse specifically, but… it is the Trinity that we are talking about after all! At no point will we ever understand God exhaustively like he understands himself. We are left, then, to enjoy the things of God revealed in Scripture. Ultimately, what we do know of God is always cause for worship. Worshiping God with heart, mind and soul, we will be eager and ready to learn what we can know about God while at the same time being content and humble about what we cannot. When it comes to the Trinity, I think the comment by Gregory Nazianzus best describes the real life experience of a thinking, praying, worshipping Christian with regard to the Trinity:
“I cannot think on the one without quickly being encircled by the splendor of the three; nor can I discern the three without being straightway being carried back to the one.”
Calvin agrees with Nazianzus and helpfully comments:
“Let us not, then, be led to imagine a Trinity of persons that keeps our thoughts distracted and does not at once lead them back to that unity. Indeed the words ‘Father,’ ‘Son,’ and ‘Spirit’ imply a real distinction—let no one think that these titles, whereby God is variously designated from his works, are empty—but a distinction, not a division.”
As Calvin says, there is a “real distinction” between the Father and the Son. Yet, it is through the Son that we see and know the Father. May the revelation of God in Christ cause us to stand in awe and bow in worship this Christmas.
 See Tertullian argue this point: Against Praxeas; In Which He Defends, In All Holy Essential Points, The Doctrine of The Holy Trinity, (ANF 3, p. 612-13). Tertullian does not seem to directly address the name of “Eternal Father” however.
 John Calvin, Institutes of Christian Religion, I. 13. 17, quoting Gregory Nanzianzus.