All Christians Must Study Theology & Study It Rightly
Psalm 111:2 says, "Great are the works of the LORD, studied by all who delight in them." The Puritan pastor and renown Bible commentator Matthew Henry comments on this verse: "All that truly love God have pleasure in his works, and reckon all well that he does; nor do their thoughts dwell upon any subject with more delight than on the works of God, which the more they are looked into the more they give us of a pleasing surprise." Like marriage, the Christian is one who is in relationship with God and steadily pursues to delight in Him more and more. The very essence of eternal life is to know God and the gospel of grace (Jn. 17:3). Therefore, to arrogantly reject studying God in the Word and the truths that the Word teaches is to reject God Himself and His salvation. The Christian is one who progressively grows in learning to delight more in God and His works of salvation.
Wrong Ways To “Do Theology”
Theology is the study of God. But, theology can be "done" wrongly. Theology is done wrongly in two main ways: 1) To study theology merely for the intellectual exercise but fail to believe its truths in such a way that changes the way we live. And, 2) To downplay the study of doctrine because of the false idea that it isn't practical and then to only look at Christian practices in such a way that are detached from delighting in God Himself.
Summary: The proper way to "do" theology is to study doctrine in such a way that begins with the head (intellect) and goes into the heart (affections/desires) and moves out through the hands (actions/practices). This is what it means to know God. To reverse this, there is no faithful Christian living that neglects the heart change that comes through knowing more biblical doctrine. At the same time, there is a way one can know "about" biblical doctrine in such a way that doesn't change their heart. That is equally wrong--if not more dangerous.
The Right Way To “Do Theology”
This means that one cannot study theology if one is not born again. John Webster says, "Christian theology is a work of regenerate intelligence, awakened and illuminated by divine instruction to consider a twofold object [which is God in Himself and all other things in existence as they relate to God]." Unbelievers--whether self-proclaimed atheists, those of other religions, or hypocrites--cannot do theology in the way the Bible describes. And that is the only right way to do theology. The primary need for anyone to study theology rightly is that they be born again (Eph. 2:1-10).
Now, when one begins this great work of studying God, His works, and all things in existence and how they relate to Him, one must always keep God as the center of all topics. You will never know ethics when you lose sight of God. You will never rightly seek justice when you neglect who God is and His gospel of grace. You will never rightly know how to get to the heart and counsel someone most faithfully when you put God off to the side. Nothing will make sense when we detach it from the God who creates all things and sustains its very existence. Therefore, dear believer, you will never know yourself, your family, your work, your responsibilities, or how to live in this world when you neglect studying God and relating all things to Him and His gospel of grace. Knowing God is the end in itself. And because of this fact, nothing else will make sense when you neglect the study of God. For knowing God illuminates how you know everything else and how it relates to God.
Practical Suggestions
Where should you start? Let me highly suggest that alongside reading your Bible, private prayer, and the diligent attendance of the public means of grace (preaching, praying, sacraments) that you also pick up great books that help teach us who God is. Every doctrine in the Christian life comes from the foundation of the Doctrine of God. That means we ought to study the Trinity and the attributes of God. For a more devotional work, consider picking up Mark Jones' work titled God Is. For another very readable book, try Matthew Barrett's book None Greater and his other work on the Trinity titled Simply Trinity. If you're looking for more in depth yet still very readable works, grab James Dolezal's fantastic book All That Is In God or even Stephen Charnock's masterpiece The Existence and Attributes of God. Trust me, you'll be surprised at how readable and enjoyable these works are and yet at the same time ones that stoke the fires of our hearts to love God more.