This can sound like one of those questions theologians like to ask akin to, “How many angels can dance on the head of a pin?” One theologian gave a joking answer to it: What was God doing before creation? He was inventing hell for those who ask such cheeky questions.
There is, however, a Scriptural answer that is very clear. Jesus says in John 17:24, “Father, you loved me before the foundation of the world.” That’s what God is doing. That means something paradigm-changing in our understanding of God.
Who is God? I think it’s very easy for us to look around at creation and see that He has mightily brought all this into being. So, who is God? He’s the Creator. He’s mighty, transcendent, awesome over all things. But many religions might say something similar. How is our God different?
Before He was ever Creator, what was God like in the privacy of eternity? A single-person god would be sitting all by himself, presumably making himself happy with his own company. However, this God, the Father, is loving His Son, which means there is an identity in God that is Fatherly. This tells you about the very nature of the gospel. It shows us that when we pray, we don’t speak merely to One who is almighty and transcendent. Rather, we can speak and say boldly as children, “Our Father,” because of who He is in eternity. That’s His identity.