How well do we understand God? Understanding God in all His fullness is impossible. In fact, Job 36:26 says that God is infinitely beyond our understanding. Does this mean we should avoid trying to know Him at all?… No, because God has made many of His traits and attributes understandable.
God has revealed Himself to humanity through His book, the Bible. By reading and studying His book, we learn who He is, how He responds, and how He revealed Himself to us. When you start trying Him the experiences you start having with Him increases your belief in Him. This allows you every time someone says God to think of a experience and respond according to that moment.