On the Surface
I think the reason many people don’t fully appreciate the Catholic faith, and for some the reason why they leave the Catholic faith, is because we often take our faith and the teachings of the Church at surface level. It’s very easy to read the 10 commandments, to hear the readings at Mass, to recite the Nicene Creed, and go to Mass, without really understanding what’s being said, or what we’re challenged to believe.
For example, we often say (as Scripture tells us in 1 John 4:8) that God is love. On the surface, it sounds really nice, and helps us feel better about when bad things happen. Yet if we really think about that statement, it doesn’t make sense unless we go deeper.
If God existed before time, before nothing existed outside of God, how could God be love? Because in order to be love, or to love, there has to be something to love. God can’t just love Himself, right?
Or can He?
God is not just the Father, but also the Son, and also the Holy Spirit. As Catholics, we believe that the Father begot the Son, and that relationship, the love between them, is so powerful, so strong, the Holy Spirit became so as to express that love.
I think that makes God so much more beautiful—that God is Love itself. That God is so much Love that that Love became the Holy Spirit.
And we can sit there and (mostly) understand that and be like, cool. Yet we just scratched the surface, because we haven’t addressed how it’s possible for God to be eternal, and the Trinity to be one God. If Jesus was begotten (created) by God the Father, and the Holy Spirit came to be out of the Love between Father and Son, and all three are one God, then how can God be eternal?
Go Deeper
The reason why God is still eternal—and not just the Father, but the Son and Spirit as well—is because God exists outside of time.
Even though we say the Father was, then He begot the Son, and then the Spirit flowed from them, we as human beings are limited and work in the confines of time, so we have no other way of describing how the Trinity is without using this then this then this happened.
But, that doesn’t (and shouldn’t) stop us from trying to understand God better. The problem comes when we don’t understand, or don’t want to understand, and so we turn away from God. That’s why science is so awesome and such a good thing (when done morally) – it helps us to understand God and His creation better.
And that’s what we’re called to do – to understand God more*. Because the more we understand God, the better we can share who God is with others.