The Orthodox Church teaches that we have knowledge of God, only because God has shown himself to his creation. God is the Lord and has revealed himself unto us; blessed is he who comes in the name of the Lord (Ps 118:26-27). Also, God's self-revelation is found in His Son Jesus Christ, the fulfillment of the gradual and partial revelation of God in the Old Testament. Jesus is the one truly "blessed ... who comes in the name of the Lord."
God is holy
According to the Scriptures, and the experience of the saints of both the old and New Testaments, God is absolutely holy. This means literally that he is absolutely different and unlike anything or anyone else that exists. He is so unique and so perfect that his existence cannot be compared to any other existence. God is absolutely transcendent, “what he is, by essence and nature, is altogether beyond our comprehension and knowledge