Begotten, proceeding … what’s the difference?

A friend asked:

In the Creed we sing that Christ the Son is begotten by the Father, and the Holy Spirit proceeds from the Father. What’s the difference?

The Fathers at Nicea used language from Saint John’s Gospel. They were concerned with the Arian heresy, so they started with “Only-begotten” and then added enough more detail so that nobody who believes the Son is not the same in nature as the Father could be baptized or ordained. That creed ended simply, “I believe in the Holy Spirit,” and then some anathemas against Arianism. It didn’t occur to them to dogmatize about the Holy Spirit since there wasn’t any controversy about him.

But within a few generations a new heresy arose – the Macedonians began teaching that the Holy Spirit was not God. The Second Ecumenical Council, at Constantinople in 381, added what is now the rest of the Creed as we know it. Following Nicea’s lead, they used language from St John’s Gospel, where Christ says, “When the Helper comes, whom I shall send to you from the Father, the Spirit of truth who proceeds from the Father, he will testify of me” (Jn 15:26).

That verse, incidentally, describes the Holy Spirit as being sent into the world, in time and history by Christ — but as to eternity, Christ says, the Spirit “proceeds from the Father.” The Fathers at Constantinople did not distinguish how the Holy Spirit’s proceeding from the Father differs from the Son’s begottenness from the Father; they could not have known that centuries later someone would change their Creed, so they didn’t see a need to add detail.

From the Creed, we learn:

• The Son is the only-begotten of the Father;
• The Spirit proceeds from the Father;
• The Father begot the Son and breathed the Spirit [breath and spirit are the same word in Greek, Latin, Hebrew.) .

In confessing this, the Church distinguishes the Persons of the Trinity: the Father, the Son, and the Spirit are not interchangeable. They each have personal characteristics not shared by the other two, because they are consubstantial (homoousios, one in essence) but not one person. When St John writes that “God is love” (1 Jn 4:16) he shows that the divine Persons eternally have relationship among themselves, which could not be the case if the Godhead were one person. (This emphasis comes around again every time the Modalism/“Jesus Only” heresy pops back up.)

This distinction also protects the dogma that the three divine Persons are co-equal because they are of the same essence. The Son is of the Father; the Spirit is also of the Father. But contra the filioque, just as the Son needs only the Father as his origin, so the Spirit does not differ by needing two divine Persons as his origin — and the Father is not diminished by needing another Person's help to breathe the Spirit. In this vein, Saint Photios (†893), Patriarch of Constantinople, wrote an exhaustive rebuttal of the filioque.

But other than using “begotten” and “proceeding” to distinguish these two Persons, the Church does not very often try to define or explain what Christ meant by these two terms. To do that we would have to speculate as to things that God has not revealed. So Saint John Damascene (†749) writes:

We have learned that there is a difference between begetting and procession, but the nature of the difference we in no wise understand.
— Exact Exposition of the Orthodox Faith, 8-9

Four centuries earlier, Saint Gregory the Theologian (†390) wrote in stronger language:

You ask what is the procession of the Holy Spirit? Tell me first what is the unbegottenness of the Father, and I will then explain to you the physiology of the generation of the Son, and the procession of the Spirit, and we shall both of us be stricken with madness for prying into the mystery of God.
– Fifth Oration, 7-8