St. Gregory the Theologian: Filioque?

The Cappadocian Fathers speak of the Spirit in the 3rd order in the blessed Trinity. St. Athanasius famously said that as the Son is in relation to the Father in order and nature, so also the Spirit is to the Son. That is a powerful testimony to the belief that the Spirit's being originates from the Father through the Son. Gregory Nazianzus, otherwise k…