I grew up in an offshoot of the Worldwide Church of God, which was
Binitarian rather than Trinitarian. What's "Binitarian" mean?
Essentially, we thought that God the Father and God the Son were God,
whereas the Holy Spirit was an impersonal force rather than the third
person of the Trinity.
An argument that I heard from a Binitarian
relative of mine was that the controversies about the Godhead in the
early days of Christianity concerned whether or not Jesus was God,
whereas the Holy Spirit was not an issue. According to him, when the
church officially declared that Jesus was God, it included the idea that
the Holy Spirit was God as an afterthought. My relative's implication
was probably that the notion that the Holy Spirit was God (or even a
personal being) was not a long-standing feature of Christian teaching
prior to the Nicene Creed. My relative supported this argument with a
scholarly entry in the International Standard Bible Encyclopedia.
As
a result of what my relative said, I've had questions about the Holy
Spirit in early Christian thought. Was the Holy Spirit believed to be a
personal being or an impersonal force? And, if the Holy Spirit was
long considered to be a personal being, did Arius address the alleged
threat to monotheism that could result from considering the Holy Spirit
to be God, since Arius had the same sort of concern about Jesus being
God?
It turns out that the divinity of the Holy Spirit was also
debated in controversies about the Godhead, and my impression is that
the various sides agreed that the Holy Spirit was a personal being.
Khaled Anatolios discusses this issue in his excellent (and readable)
essay, "Discourse on the Trinity", which is in The Cambridge History of Christianity: Constantine to c. 600.
Anatolios
acknowledges that Arius did not focus his attention on the Holy Spirit,
and that the Holy Spirit was an afterthought in the Nicene Creed. At
the same time, Anatolios states on page 441 that Arius "certainly
considered the Spirit to be a creature." Anatolios also states that the
Homoians
and Eunomius "maintained that the Spirit...was subordinate to the Son
and not an object of worship." A group called the Tropici held "that
the Spirit was created as an angel, the chief of God's 'ministering
spirits' (cf. Hebrews 1.14)." Against such ideas, Athanasius (who was
prominent in the debate about Jesus' divine status) and Basil of
Caesarea affirmed that the Holy Spirit was God. So the various sides agreed that the Spirit was personal, but they disagreed about whether the Spirit was God.