Everyone should study theology because everyone has some belief about God. Even the atheist cannot deny God’s existence without reference to some sort of belief in God. And since the idea of God always deals with questions of creation, existence, law, ethics, morals, sin, the nature and purpose of mankind, and, ultimately, what happens after we die, then it is important that we know what we believe about God.
The Christian particularly needs to study theology because Jesus has commanded that we go into all the world teaching and making disciples (Matthew 28:19-20). And there’s no way one can teach without first knowing the subject matter. One reason for this is that all teachers know that the best way to learn your subject matter is to teach it – we learn as we teach. Or, we learn as we talk about it, not necessarily in a formal teaching setting. But the idea is that of communicating these idea about God to others and in the process, we learn, too.
Studying theology and doctrine has a very practical benefit to us. It helps us overcome wrong ideas and helps us make better decisions as a result. You can’t do better if you don’t know better. And in the Word of God we have the help of the One Who knows everything. The Bible teaches us that we shouldn’t lie and we see the negative effects of lying all around us. We actually have laws on the books that match up with the Ten Commandments and we ignore those at our own peril! Or take the Biblical view of monetary debt. How many heartaches and heartbreaks would couples and individuals be spared if they only stayed within their means? But why did they spend more than they made? Could it be because they weren’t patient? Or, maybe they were coveting something and really wanted it, even though others warned them about it? A Biblical doctrine of contentment or a Scriptural view of work would certainly have had an effect if only heeded.
Theology also helps us grow and mature. As we live and deal with the various joys and disappointments in life, Biblical doctrine helps us to keep the right perspective. It helps us to learn from our own and others’ mistakes. We learn to avoid certain things and practices because of what Scripture teaches, but also because we’ve experienced the truth of Scripture first-hand.
Probably the main reason to study theology, though, is this is how we learn about God and ourselves. We can’t know God without learning about ourselves, and we can’t learn about ourselves without knowing about God. This is how John Calvin begins his Institutes – “Our wisdom, in so far as it ought to be deemed true and solid wisdom, consists almost entirely of two parts: the knowledge of God and of ourselves.” He later states, “we cannot aspire to Him in earnest until we have begun to be displeased with ourselves.” It is theology from God’s Word that helps us do that.