On some level we still believe this today. That's why we give nicknames to our friends as we grow, highlighting some important trait about them. This name was given by an angel. That day, at Jesus's circumcision, Mary and Joseph were reminded that , even though things were becoming routine and all the excitement was over, God's work in the life of their family was just beginning. They were reminded where this child came from- they were given an intriguing hint of where this child was going.
Salvation is in that name.
Today we go through a naming ceremony of sorts too. We have a chance to start over again, to become new. People know you go to church. People think of you as a Christian. Meditate on that today.