When it comes to your relationship with God, “head knowledge” is so important. The whole “just-love-God-with-your-heart” motif won’t work. After all, you can’t possibly love God with your heart without knowing something about God in your head. To attempt to do so is nothing short of insulting, unloving, and nonsense.
Let me explain.
Suppose that, over dinner, my wife begins telling me things about herself – that is, about her desires, her hobbies, her passions, her preferences, her dislikes, her thoughts, her past, her plans for the future, etc. But before she can even finish, I interrupt her, saying, “Oh, honey. I don’t care to know anything about you; I just want to love you.”
My words in that illustration are nothing short of silly. How can I ever love her if I don’t care to know anything about her? (By the way: Don’t buy the line that someone loves you if they are not interested in learning things about you. Such “love” is superficial and, often, exploitive. When you love someone, you study them.)
Sadly, though, this is the same route many of us evangelicals take in our relationship with God. We aren’t too interested in learning about him; we just want to love him. Don’t get me wrong. We need to be cautious about falling into the trap of just having “head knowledge” such that we forget to love God with our hearts (that would be a terrible mistake, to be sure). That said, it could be said that we have become so cautious about this that we have swung too far the other way, failing to notice when we’ve made the opposite mistake of trying to “love God” without being interested in knowing anything about him.
In the end, learning about God is important because loving God is paramount. If we love God, we’ll study him. That’s why theology matters.