How great is God -- beyond our understanding! The number of his years is past finding out. (Job 36:26)(NIV)
There are many things about God that we will never comprehend. What does it mean for God to be self-existent---to have no beginning and no end? Such a mystery is beyond understanding. But the fact that we can never comprehend God for all that He is does not mean that we cannot have a meaningful relationship with Him.
God has most fully revealed himself to us by sending his Son Jesus Christ (Heb. 1:1-3). Jesus said, "Anyone who has seen me has seen the Father" (John 14: 9). By pursuing and cultivating a relationship with Jesus Christ, we come to know God through a being of flesh and blood. As Moses said to the people of Israel, The secret things belong to the Lord our God, but the things revealed belong to us and our children forever (Deut. 29:29).
(from the Quest Study Bible - Zondervan)