I see this statement as laying the foundation of our understanding of what God is, thereby eliminating, first, all those who say otherwise. It's a broad and general statement about God and brings us to humility in two ways i) by expressing the greatness and power of God, and ii) by setting the stage for our contemplation of God by beginning first with the simple and certain points that we know and treading carefully when including more defined and specific terms.
We know from this statement that there is one god, and that He is responsible for the existence of all that is. It produces the imagery of a father, one who protects, provides for and loves His children, not just that of a detached and disinterested authoritarian; but then it is made clear that He is the Almighty. I think this is interesting, that the role of Father is placed before that of Almighty: we know that in Greek word order is flexible and rather is often used to express emphasis, so the choice here to place the role of Father before that of Almighty speaks volumes about His mercy and love for those whom might be called His children.