One of the doctrines of Christianity is that God is incomprehensible, yet knowable. His incomprehensibility lies in the fact that He is God and infinite—He is Creator and we are His creatures, and His knowability lies in the fact that He is God who has chosen to reveal Himself. Without revelation no human being could ever assert to know God partially, and even with revelation no human being can ever say that they know God exhaustively. Therefore all knowledge of God is dependent upon the revelation of God.
The nineteenth century Dutch theologian Herman Bavinck states,
“..the knowledge of God can have its origin only in revelation. Naturally, if God does not become manifest in his creatures, no knowledge of him is even possible. But if he does display his perfections in the world of creatures, his knowability can no longer be disputed…God’s incomprehensibility, so far from canceling out God’s knowability, rather presupposes and affirms it. The riches of God’s being—riches that surpass all knowledge—are in fact a necessary and significant component of our knowledge of God. The fact remains that God makes himself known to us in a manner and measure in which he reveals himself in his creatures.” (Reformed Dogmatics: God and Creation, 56)
In light of this, the knowledge of God that Christian’s have should always be soaked in humility. Knowledge of God is a gift from God. (So don’t act like it aint.) If and when this is forgotten human pride sets in.
Christians are called to assert God’s incomprehensibility and his knowability, which means that Christianity proclaims real truth about God and is to do so humbly and boldly. God is knowable so we can boldly proclaim him, and He is incomprehensible so we should humbly proclaim Him. Rejecting His incomprehensibility makes for a self-righteousness believer, and rejecting His knowability makes for a skeptical unbeliever.
As Francis Schaeffer has said, God is there and He is not silent. He has spoken in sky. He has spoken in the Scriptures. And He has spoken in Jesus.
The incarnation is the epitome of God’s self-revelation, and reveals that God has not abandoned the world that He created, nor did He create the world and leave it to its own undoing by just telling humanity what they should and shouldn’t do and enjoy watching them fail, but it reveals that He loves the world and has taken on human flesh to bring sinful human beings to Himself. The first human beings, Adam and Eve, rejected God’s revelation and all humanity thereafter has as well: making gods out of themselves or other created things. But God did not stop revealing himself because humanity stopped listening.
God promised to come through the patriarchs and prophets of the Old Testament to save his people, and came in the person of Jesus of Nazareth to forgive sinners. As Jesus’ best friend John put it, “[Jesus] has made [God] known” (John 1:18). The New Testament is the written revelation of the God-man, Jesus Christ, who is the final word of God to the world and the “exact imprint” of God’s nature (Heb. 1:1-3).
Being a theist is not enough. Knowing about God is not enough. Trusting God’s generous gift of Himself in the person of Jesus Christ to a rebellious world of which you are a part is the way to know God. If you believe this, this should make you humble and bold—confident in who God is and what he has done for you and for the world in the person of Jesus Christ, and humbly amazed at the same. Humbled because God has spoken and saved you who did nothing to deserve His revelation nor His salvation, and many times along the road of life ignored it, suppressed it, and flat out rejected it.
Revelation and salvation are both rooted in grace. God is the one who has made a way for you to know Him. It was His desire, and His idea.
No, belief in Jesus does not mean you know everything, but it does mean you know God. As Jesus himself put it, “Whoever has seen me has seen the Father” (John 14:9). Knowing Jesus does not mean you know God exhaustively, but it does mean you really know him. Because of grace you can begin to plumb the “depths of the riches and wisdom of the knowledge” of the “unsearchable” and “inscrutable” God of the universe (Romans 11:33).