The doctrine of God encompasses the Christian description of the Triune God’s being or essence as well as God’s names, attributes, and works according to Scripture.
The doctrine of God is the horizon of all Christian theology. It’s built into the very name “theology”: it’s “logos about theos“—that is, “speech about God.” That’s why people sometimes call the doctrine of God “theology proper,” meaning that theology is actually talking about the doctrine of who God is in his essence, in his existence, in his attributes, and in his eternal being as Father, Son, and Holy Spirit. In a sense, if you call the doctrine of God “theology proper,” all the other subjects you’re going to talk about in Christian doctrine are, in some ways, improperly theology—that is to say, we just extend the notion of theology to cover all the other fields because we talk about all the other things in light of their relation to the doctrine of God.
This is what theology exists for: to speak about God. Theologians can dabble in various areas and feel relatively safe talking about some areas of Christian doctrine in various ways. But as soon as they raise their eyes to the very purpose of theology, they often put their hands up to their mouths and say, “I need to take this seriously, because now I am speaking of God.”
The subfields inside the doctrine of God include the discussion of God’s existence—especially whether that can be proven by necessary proofs of reason. Also included is a biblical-theological study of the names of God—that is to say, God’s own self-naming as he authoritatively reveals how he should be addressed and thought about and spoken of. You can also talk about ways of naming God analogically from our own experience and understanding. And there’s a vast field of God’s “attributes”—the divine perfections, all of the things that make him God. God is not cobbled together from a bundle of attributes but actually is the one God who has all of these perfections in transcendent simplicity.
The heart of the doctrine of God lies not in the question of what God is, nor in exploring the divine perfection and attributes, but in God’s self-revelation that he is eternally the Father in relation to the Son in the unity of the Holy Spirit. He is the Triune God who is both one in essence and three in persons.
There is a tradition of treating God’s decrees for the world and the order of all things as part of the subject matter of the doctrine of God itself, giving attention first to God’s dispositions and decisions before turning to God’s outward works, so that the final discussion in the doctrine of God is of the divine decrees.
• Ps 103
• Dt 6:5
• 1 Jn 1:5
Sanders, F. (2018). The Doctrine of the Triune God. In M. Ward, J. Parks, B. Ellis, & T. Hains (Eds.), Lexham Survey of Theology. Bellingham, WA: Lexham Press.