CS Lewis’ amazing description of the Trinity.

That Son exists because the Father exists: but there never was a time before the Father produced the Son…In the same way we must think of the Son always, so to speak, streaming forth from the Father, like light from a lamp, or heat from a fire, or thoughts from a mind. He is the self-expression of the Father—what the Father has to say. And there never was a time when he was not saying it. …And that, by the way, is perhaps the most important difference between Christianity and all other religions: that in Christianity God is not a static thing—not even a person—but a dynamic, pulsating activity, a life, almost a kind of drama. Almost, if you will not think me irreverent, a kind of dance. The union between the Father and Son is such a live concrete thing that this union itself is also a Person. …This third Person is called, in technical language, the Holy Ghost or the “spirit” of God. Do not be worried or surprised if you find it (or Him) rather vaguer or more shadowy in your mind than the other two. I think there is a reason why that must be so. In the Christian life you are not usually looking ‘at’ Him: he is always acting through you. If you think of the Father as something ‘out there,’ in front of you, and of the Son as someone standing at your side, helping you to pray, trying to turn you into another son, then you have to think of the third Person as something inside you, or behind you. Perhaps some people might find it easier to begin with the third Person and work backwards. God is love, and that love works through men—especially through the whole community of Christians. But this spirit of love is, from all eternity, a love going on between the Father and Son.” (CS Lewis, Mere Christianity, “Good Infection”)