Logion 4

4. Jesus said, "A man old in days who suffereth not, but asketh a small child of seven days about the place of life, that man will live. For there are many among the first who will be last, and they will be one and the same."
Cf. Mk 10:14-16, 31
And they brought young children to him, that he should touch them: and his disciples rebuked those that brought them. But when Jesus saw it, he was much displeased, and said unto them, "Suffer the little children to come unto me, and forbid them not: for of such is the kingdom of God. Verily I say unto you, 'Whosoever shall not receive the kingdom of God as a little child, he shall not enter therein.'" And he took them up in his arms, put his hands upon them, and blessed them. "…But many that are first shall be last; and the last first."
Hippolytus quoting from the Gospel of Thomas in Ref. V. 7:20
"He who seeketh me, will find me among the children of seven years, for there hidden in the fourteenth aeon shall I be revealed."
Manichaean Psalm Book p. 192, 2-3
"The grey haired men the small children instruct them. Those who are six years old instruct those who are sixty."

The small child is extraordinarily perceptive of spiritual realities. A man who is old will do well to take a lesson from a child so fresh from the presence of God. It may be that we order our society so that the oldest is placed first, and the youngest last, but with God temporal age is of no consequence. Spiritual development is not measured in years. This is an appealing concept. It is disappointing that it was not better preserved in the canon.