Why do you think the poet feels that his childhood had hidden itself in a infant's face?

The poet thinks so because all the people in their childhood are almost the same. Children's behaviour ,their activities and their innocence makes him feel that his childhood has hidden itself in some infant's face as he was also like them in his childhood.He also believed in hell and heaven, didn't knew any hyocrisy and just believed in whatever his parents or other persons would say in his childhood. Now he is able to see all these features in other children.