The Trinity of Eastern Orthodoxy: the Holy Spirit flows from Father eternally. This is in contrast to the Catholic filioque, in which Son and Father are at the same horizontal level, from which the Holy Spirit flows, forming a triangle.
Orthodoxy prevails here, for the Trinity is a line, not a triangle.
The Father is Love, the Loving Beloved whose Love breathes a cosmos in loving submission. The Son is the Logos of Truth. The Son follows from the Father because Love is relational, Love has a direction: Love entails a Lover and a Beloved. So Love entails that God should breath the cosmos. The Son is Truth because only Truth can be come from the ruh (breath) of God. This action of breathing is the relationship of Holy Spirit from the Loving Beloved to the Loving Son. God’s most beloved lover is the Logos of Truth that God breathes in love.
But in turn, from our fallen perspective, the Beloved Truth is buried within us, sublimated within us, forms a body of difference, a logic of life upon which we can strive to attain Love in Cosmic Romance. (We sometimes call this sublimated body the Gifted Body, but more on that another time.) It is this Romance that makes our life into a journey, but also makes our love the strongest above that of other, immediately submissive entities.
That original breathed Word is still within us, but sublimated, so Truth walks with us, but we cannot see. Its sublimation makes our lives of difference possible.
So what does it mean to say the Spirit descends upon us? It is the mechanism of Truth. The Spirit descends upon us and Truth is breathed into us. Wisdom, Sophia, emerges.