The first Christian missionaries preached the gospel in a pagan, polytheistic world. They preached that there was only one God, and they also preached Jesus Christ as God. It was not long before people wondered how these ideas could both be true.

The gentiles needed to know how the Christians could claim to be against polytheism if they saw nothing wrong in worshiping the Father, the Son, and the Holy Spirit. Christians responded by expounding scriptural concepts that centered on God’s unity. The development of these concepts led to the church synods, or councils, that formulated the doctrine of the Trinity. Even then, controversy raged for decades. Two major heresies loomed in the struggle for understanding God’s nature. These heresies resulted from sincere but misguided efforts to simplify the scriptural presentation of the three-in-oneness of the Godhead.

1) Modalism. Some believed in the unity of God – that God is one – but explained that the Father, Son, and Holy Spirit were merely three “modes of revelation,” masks, so to speak, under which the one God had revealed himself to humans at different times. Sometimes God presented himself as the Father, sometimes as the Son, and sometimes as the Holy Spirit. Modalism denied the biblical teaching that the Father, the Son, and the Holy Spirit exist simultaneously. The modalist view was rejected because it meant that Jesus would have had to pray to himself, and the Father would have died on the cross.

2) Arianism. This teaching also defended the unity, or oneness, of God, but it asserted that only the Father is God. Arians believed that Jesus Christ was created and therefore belongs to the created order, as the first and highest creation of God. Arius (ca. A.D. 250-336) and his followers saw the Holy Spirit as the first of the Son’s creations.

Athanasius (ca. A.D. 296-373) opposed Arius, holding to the unity of God but seeing three co-essential hypostases in God. Athanasius said the Son is of the same substance or essence as the Father (thus he is “co-essential”) and that the Son is eternally generated of the Father. Thus the Son “eternally proceeds” from the Father. He is the Son from eternity. He is also the Son by virtue of his incarnation on earth. God is one being, but three hypostases — one being, but three Persons.

The Roman emperor Constantine supported, at first, the Athanasian view, which was accepted at the Council of Nicea (A.D. 325). Constantine soon reversed himself, however, and persecution against supporters of the Nicene decision ensued. It was not until the Council of Constantinople (A.D. 381) that the church leaders finally adopted what is now known as the Nicene Creed, which described God as one divine being existing in three, co-essential hypostases, or persons.

In the sixth century, the Western church (Roman Catholic) came to believe that the Spirit proceeds from both the Father and the Son, while the Eastern church (Eastern Orthodox) retained the Nicene view that the Spirit proceeds from the Father. It was unfortunate that this disagreement alienated Christians from one another.

All Christians realize that any humanly worded formula cannot really describe God with complete accuracy. Thus the Trinity has been described as a mystery. It is often accepted on faith, with the admission that it cannot be perfectly understood. The Bible gives us these facts: There is one God, and the Father is God, and the Son is God, and the Holy Spirit is God. The doctrine of the Trinity affirms these biblical facts without contradicting the Bible.

It goes without saying that a finite, flesh-and-blood human being cannot possibly fathom the fullness of the transcendent God. Even the fullness of God’s love, which we humbly acknowledge, is beyond our limited grasp. The apostle Paul describes it as a love “that surpasses knowledge” (Ephesians 3:19). We shall never come to a complete knowledge of God, but God has given us the intellectual tools to know at least that he is the Creator, the Author of all things, the Giver of life, and a being whose nature is far greater than human beings can possibly imagine or explain.

But more than just knowing about God, God also wants us to know him in a personal way. He has not only revealed facts about himself as the Creator, but he has also revealed his love for us. In the next chapter, we will learn about the relationship that God has with human beings.