To begin, lets hold two ideas in our mind:
- During the birth of Christ we see that Angels show up a whole lot.
- The author of Hebrews tells us that the word spoken by Angels was steadfast (Hebrews 2:2). That is, in the Drama of Redemptive History, God oftentimes used Angels as a trusty means by which to communicate revelation.
Angels Show Up A Whole Lot
- In the first chapter of the Gospel of Matthew, an Angel instructs Joseph (who had legitimate concerns about Mary's having become pregnant) to not be afraid to take Mary as his wife.
- In the second chapter, an Angel instructs Joseph to flee blood-thirsty Herod and take Mary and the baby Jesus to Egypt.
- After Herod is dead an Angel instructs Joseph that it is safe to return.
- In the first chapter of the Gospel of Luke, an Angel appears at the right side of the altar of incense before Zacharias; the Angel tells him that he and his wife are going to have a son (John the Baptist), and that this son will "make ready a people prepared for the Lord."
- Also, later on the angel Gabriel greets Mary and tells her that God's favor is with her and that she will become pregnant by the power of the Holy Spirit and that she will bring forth a son, and that his name will be Jesus, which means "Jehovah [in the Old Testament this is the proper name of God] is Salvation".
- In the second chapter of the Gospel of Luke, after the birth of Jesus the Angels appear before the shepherds in the fields and tell them the good news that "unto you is born this day in the city of David a Saviour, which is Christ the Lord."
In the Old Testament there are many narratives where Angels show up to declare God's deliverance. In Exodus 3, an angel of the Lord shows up and tells Moses that the Lord is going to use him to deliver Israel from bondage in Egypt. In Judges 6, an angel of the Lord meets with Gideon and tells him the Lord is going to use him to deliver Israel from the Midianites. And later on in Judges, an angel of the Lord tells Samson's parents that their son will deliver Israel from the Philistines.
Since angels were used to reveal, call, and commission deliverers in Israel's history, it should come as no surprise that God uses them again to declare the Chief-Deliverer of the mother promise (see Genesis 3:15).
This Chief-Deliverer is Jesus -- "Jehovah is Salvation" -- Christ the Son of God.