Reading Cyril of Alexandria’s (5th century church father) commentary on John’s gospel is a treat. Here is a portion of Cyril commenting on the latter part of John 8, where Jesus says “Before Abraham was, I AM.” Notice how Cyril directs us not to what God is (his being), but who he is (his attributes as Scripture defines them).
Cyril wrote that it is good and proper for us to have “fit and due thoughts” of God. He goes on to say that “no sober minded person would enquire what God really is by nature” because it is “impossible to find out.” The way we have fit and due thoughts of God is by determining what things “are his attributes and what things are not his attributes.” These attributes a person may “with ease” recognize “if one is conversant with the sacred Scriptures.”
“For we know and have believed that he is mighty, we know that he is not infirm, we know that he is good, we know that he is not bad, we know that he is righteous, and again that he is not unjust. We know that he is eternal, we are agreed and believe that he is not bounded by time, nor yet transitory, as we are.”
Beautifully, after these words, Cyril applies them to Christ as well: “He who is of God by nature is true God and he that is begotten of an eternal Father is eternal as he who begat him.”
Quotes can be found on page 675 of Cyril’s Commentary on the Gospel According to St. John (London: James Parker & Co., 1874).
Additional note: this entire commentary (along with scores of others) can be found on www.books.google.com (use the advanced search to save time).