The precise meaning of words is and has been extremely important in the life of the church. Throughout church history, orthodoxy has hinged on small changes in meaning from one term to the next. Perhaps one of the most significant examples of this phenomena was the development and usage of the terms used of the Trinity in the 4th century.
The immediate context for the development of Trinitarian language began with Arius. Arius was a priest in Alexandria who taught that Jesus was not eternal and that there was a time in which he did not exist. According to Arius, Jesus created all things and is preeminent, but is not eternal, and therefore, not God. The Council of Nicaea met in 325 and condemned and exiled Arius. It also produced an extremely important creed. This is not the Nicene Creed we know today. That creed was a product of the Council of Constantinople in 381 and is perhaps more accurately titled the “Niceno-Constantinopalitan” creed. The creed of Nicaea reads:
We believe in one God Father Almighty maker of all things, seen and unseen:
And in one Lord Jesus Christ the Son of God, begotten as only-begotten of the Father, that is of the substance (ousia) of the Father, God of God, Light of Light, true God of true God, begotten not made, consubstantial (homoousias) with the Father, through whom all things came into existence, both things in heaven and things on earth; who for us men and for our salvation came down and was incarnate and became man, suffered and rose again the third day, ascended into the heavens, is coming to judge the living and the dead:
And in the Holy Spirit.
But those who say, “There was a time when he did not exist,” and “Before being begotten he did not exist,” and that he came into being from non-existence, or who allege that the Son of God is of another hypostasis or ousia, or who is alterable or changeable, these the Catholic and Apostolic Church condemns.
The church had definitively dealt with the threat of Arianism, but the resolution was one that did not exclude Monarchianism. Nearly sixty years later, the church was faced with condemning the Monarchian teaching that emphasized God’s oneness at the expense of his threeness. This includes various forms of modalism (Sabellianism being the most notable) that fall under Monarchianism’s larger heading. The Nicaean Creed of 325 stated that the Father and the Son were of one substance (homoousias) and that anyone who alleged different hypostases or ousiai stood condemned.
Many in the East (led by Basil of Ancyra) rejected the identification of the Father and the Son’s ousiai because it sounded too much like the Sabellian teaching. As a result, they began using the term homoiousias as a substitute. The addition of the iota in Greek changed the meaning of “one substance” (homoousias) to “like substance” (homoiousias).
The church lacked the language needed to express the distinctions within the Trinity while maintaining the one essence (homoousias) of God understood in a non-Sabellian fashion. At Nicaea (325), hypostasis and ousia were synonyms. Holding to a distinction of either within the Godhead was heresy. Between Nicaea (325) and Constantinople (381), however, the church, through the efforts of Athanasius, Gregory of Nyssa, Basil, and Gregory of Nazianzus (the latter three are collectively known as the Cappadocian fathers) settled on a new meaning for the term hypostasis. Hypostasis came to be used for “persons” whereas ousia remained in use as “essence.” The church now recognized the Father and Son as distinct hypostases (persons) in one ousia (essence) related by perichoresis, or “full mutual indwelling of the three persons in the one being of God.”
Men were condemned at Nicaea (325) for proclaiming a distinction of hypostases in relation to the Godhead, but a distinction using the same word, albeit a completely different meaning, was solidified as orthodox in 381 at Constantinople.
