“When, therefore, He made us new by the remission of sins, He made us men of a different stamp, [cf. Ephesians 4:22-24] with the result that we have the soul of little children, as we should have if He were to fashion us anew.”
(Epistle of Barnabas 6:11, ca. 97, in Ancient Christian Writers 6:45)
“And when a child has been born to [Christians], they give thanks to God; and if moreover it happen to die in childhood, they give thanks to God the more, as for one who has passed through the world without sins.”
(Aristides, ca. 125, Apology 15, in Ante-Nicene Fathers 9:277-278)
“Hold fast to simplicity of heart and innocence. Yes! Be as infants who do not know the wickedness that destroys the life of men.”
(Hermas, The Shepherd 2:2:1, in Fathers of the Church 1:259)
(thanks to Errol Amey for sharing this recently in a facebook group)