The 'city of Judah,' as in Isaiah 40:9, signifies the doctrine of love towards the Lord and love towards our neighbor.

(References: Apocalypse Explained 850)

A boy (Genesis 18:7) signifies the natural man, and consequently, he who ministers and attends to others.

In Genesis 22:3, boy signifies the Lord's former rational principle that was merely human.

(References: Arcana Coelestia 2181)