When Moses asked, "What is his [God's] name?" God declared, "I AM THAT I AM." God is the only I, or Ego. He alone is the all-seeing, all-acting, all-knowing. He is the only Life, intelligence, individuality, substance, and power. When Christ Jesus said (John 2:19), "Destroy this temple, and in three days I will raise it up," the I to which he referred was God, and not himself. Man is never the I, or Ego, but he is the reflection or manifestation of God, the perfect child of the perfect Father-Mother.
In the Christian Science textbook, "Science and Health with Key to the Scriptures" by Mary Baker Eddy, "I" and "Ego" are defined jointly. The definition reads in part (p. 583):
"I, or Ego. Divine Principle; Spirit; Soul; incorporeal, unerring, immortal, and eternal Mind.