An extract of my commentary on the Gospel of Thomas:
(67) Jesus said, "If one who knows the all still feels a personal deficiency, he is completely deficient."
“The all” could easily be interpreted in two ways here: 1) all of possible knowledge, and 2) God, in the Gnostic sense of the Monad, the indefinable – the all. But what does it matter if you know God and do not know yourself (“a personal deficiency”), for if you fail to know yourself, you technically fail to know God, and are therefore “completely deficient”. This effectively explores the idea of “knowing God, but not knowing oneself” as being an illusion, and the truth of one’s own divinity serves to dispel this illusion and allow you to truly know “the all”.