It's easy enough to deduce from our world of ceaseless becoming that there must be a Being behind all the change; similarly, that before all the secondary effects there must be a First Cause. Therefore, God is the Cause of causes and the Being of beings.
Is it that simple? Yes and no. Yes because God is undoubtedly the First Cause. But it seems to me that -- bearing in mind what was said in the previous post about the Trinity -- he must also be the "first effect," so to speak. In other words, if the Father is the First Cause, then the Son must be the First Effect.
However, both the Cause and the Effect are beyond or before time (at least our kind of time). Therefore, we can't think of these as analogous to atoms or billiard balls. Then again, even in our world we can't really make a radical separation between causes and effects. Where is the line between the singer and the song, or dancer and dance? Yes, we can always point to one or the other, but only in an abstract way.
This is why early Christian thinkers took so much trouble to emphasize that Father and Son are distinct but not separate: two persons, one substance. Therefore, this relation is and isn't analogous to the relationship between, say, me and my son. My son came after me, but in time. In the Trinity the Son comes after the Father, but in eternity.
How are we to think of this? Doesn't this negate the meaning of "after"? Well, first of all, we have to think of it in the vertical sense.
For example, imagine a chandelier held by a chain. Each link is held by the one directly above, but this isn't a temporal sequence; rather, it is happening now, much like how the letters you're reading at the moment are conditioned by words, words by sentences, sentences by paragraphs, etc., all in service to the meaning you simultaneously extract from them. Imagine looking up each word in the dictionary and trying to add them up to the meaning. You'd never get there.
You can look up "father" and "son" in the dictionary, but that won't get you far. In fact, it will only enclose your mind in a circle, since each refers to the other. But what if we start with the meaning of the terms? What could that be?
Let me guess... Love? Holy Spirit? Here again, we can't think in linear or temporal terms, for each of these three occurs simultaneously. You could say that the relation of Father and Son is the "cause" of the Holy Spirit; or, you could say that the Holy Spirit is the cause of the relation. Just don't think of it as a temporal cause.
With this in mind, I think we have the foundation for a kind of "effect" in God, so long as we don't confuse it with the kinds of effects that occur down here. Let me just cut to the chase: yes, God is the First Cause. But he is also the First Effect.
Likewise, he is the Supreme Being. But he's also the Supreme Becoming.
He is the Unmoved Mover. But he is also the Eternally Moved (moved by love, or love is drained of meaning; he also loves truth and beauty, without, of course, being separable from them).
He is one without a second. But he is also two without separation. And three with even less.
He is creator. He is also creativity and creating.
He is timeless. And the best time ever (which passes so quickly it might as well be timeless).
Finally, he is Absolute. But can relate to everyone and everything. It's why, for example, he wants us to pray. He wants us to relate to him. You might say it's his weakness, which is his strength.
Let me emphasize here that this is just my opinion, man. I like to think of God this way, partly because I can't think of him in any other way. So, I agree with Hartshorne, who writes that
God is neither being as contrasted to becoming nor becoming as contrasted to being; but categorically supreme becoming in which there is a factor of categorically supreme being, as contrasted to inferior becoming, in which there is inferior being. Both poles have two levels, analogically but not simply comparable.
If we believe in God we should not say, "I believe in God," but rather, "God believes in me." --Dávila