You Tube Theology

The Father did not choose to become Father at some point. If that were the case, if he decided, "Do you know what? I'm going to have a Son," and he becomes a Father—if that were the case, then we could ask, "Well, what sort of God was he before he became Father? What's he really like deep down?"

No, Nicea is saying the Father has his very identity as Father. "We believe in one God, the Father"—that's a statement about who he is most really and deeply as a person. God is the Father begetting the Son.