Questions about the knowledge of God too quickly often turn very quickly toward the issue of sources-where does our knowledge of God come from?
John Calvin, whom I have been reading lately, deals with those issues. But after discussing what sort of knowledge of God we gain through creation, he turns toward the manner in which we ought pursue our knowledge of Him:
And here again we ought to observe that we are called to a knowledge of God: not that knowledge which, content with empty speculation, merely flits in the brain, but that which will be sound and fruitful if we duly perceive it, and if it takes root in the heart. For the Lord manifests himself by his powers, the force of which we feel within ourselves and the benefits of which we enjoy. We must therefore be much more profoundly affected by this knowledge than if we were to imagine a God of whom no perception came through to us. Consequently, we know the most perfect way of seeking God, and the most suitable order, is not for us to attempt with bold curiosity to penetrate to the investigation of his essence, which we ought more to adore than meticulously to search out, but for us to contemplate him in his works whereby he renders himself near and familiar to us, and in some manner communicates himself.
Calvin's devotional theology is grounded stems from separating God's essence from His effects. In his essence, God is unknowable and only to be adored. He communicates himself to us through his works only "in some manner," but not completely.
This preserves a sense of perpetual mystery and wonder, while placing the burden for our knowledge of God upon God and not upon ourselves. We ought not give in to idle speculation, but wait for the perception of God to "come through to us." We are passive, not active, in our perception of His divinity.
Fundamentally, it is God who allows Himself to be known to us, and in our knowing we are free to cease from activity and engage in worship. Only then will the knowledge of Him take root in our heart and will we be changed.