Arcana Coelestia # 10508
10508. 'Behold, My angel will go before you' means that Divine Truth will still be the leader. This is clear from the meaning in the highest sense of 'the angel of Jehovah' as the Lord's Divine Human, and in the relative sense as that which is Divine and the Lord's among angels in the heavens, dealt with in 1925, 2821, 4085, 6831, 9303, so that it means Divine Truth, 8192; and from the meaning of 'going before you' as being the leader.
Child
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.