A child is a young boy or girl in the care of parents, older than a suckling or an infant, but not yet an adolescent. "Children" are sometimes used as a name for a large group of descendants of one person, such as the Children of Israel, or even all human beings as the Children of Men. A child represents innocence and charity, where innocence is the willingness to be led, and charity is love. This is why Jesus blessed them and suggested that we all become like children in order to enter heaven.

In the most ancient church, their method of expressing themselves was such, that when they mentioned material and worldly things, they thought of the spiritual and celestial things that were represented. So they not only expressed themselves with representatives, but also lowered their thoughts into a kind of historical series, or arrangement, to give them life, and in this they found the greatest delight and entertainment. Those representatives are called 'hidden sayings of old,' in David's Psalm 78:2-4.

(References: Arcana Coelestia 66)