Book 1:

Reason alone teaches us to know good and bad. . . . Before the age of reason we do good and bad without knowing it, and there is no morality in our actions. . . . A child wants to upset everything he sees; he smashes, breaks everything he can reach.

Book 4:

We hold that no child who dies before the age of reason will be deprived of eternal happiness. . . . The whole difference I see here between you and me is that you claim that children have this capacity [i.e., to recognize the divinity] at seven, and I do not even accord it to them at fifteen.