In the Orthodox Church, when we celebrate a feast commemorating an event in our salvation history, such as Pentecost, also known as Holy Trinity Sunday, it is followed directly by another feast honoring a person who figures heavily in the previous day’s event. In the present case, tomorrow is Holy Spirit Day. It seems a good time to post these thoughts from Metropolitan Anthony:
When we say that God is spirit, we say simply that he is not matter as we know it, that he is something quite different. In that sense it is a negative description that belongs already without the word, to that form of theology which is negative theology, apophatic theology, a theology of paradoxes, a theology that uses words to point toward the ineffable — that which can neither be described nor put into words and yet which must be indicated somehow in speech.
One could avoid speech. In Siberia there were pagan tribes that had deliberately rejected every human word for God. And when in conversation they wanted to indicate God they raised their hand towards heaven. This is possible in a civilization of direct communication by speech. It is no longer possible in a civilization of books. But whatever words we use we have got to be aware of the fact that we are not describing, we are not defining what God is, because the very thing we know about God is that he is beyond defining, beyond describing. So that when we say of God that he is a Spirit, when we speak of the Holy Spirit in particular, we do not mean to give a concrete definition or any description of what he is. We point towards the fact that he is beyond our conceptual knowledge, beyond every formulation, that is is what we don’t know, and this is what we mean to say by saying that he is a spirit as contrasted with us.
–Metropolitan Anthony Bloom, excerpt from “Our Life in God,” from Essential Writings

Pentecost icon (fresco)
This weekend many of my friends all over the world are celebrating Easter. To help convey my own warmest greetings on the blessed Resurrection Day I’m passing on a message from 
“What, I ask, is the truth of water? Is it that it is formed of hydrogen and oxygen? … There is no water in oxygen, no water in hydrogen: it comes bubbling fresh from the imagination of the living God, rushing from under the great white throne of the glacier. The very thought of it makes one gasp with an elemental joy no metaphysician can analyze.