Jesus's birth was for told to the serpent by God himself after Satan used it to tempt Eve but his real gold , was to get to Adam . Genesis 3:35.
The name Jesus means Emanuel, God with us .
I will get to the name part in a moment, but first i want to show my readers why God had to become a man .
Point 1. - God is a spirit and a spirit dose not have blood to offer up as a offering for sin.
Point 2. God being a spirit is not subject to dying , for only as a man could he die which is the second reason why God had to become a human being.
Point 3. The Earth was lost though a man so it would take a man to win it back, next The Law was given by Moses but, it was trying to change unsaved human beings which still had a sinful nature in them because of Adam.
All of these and more is reasons why God had to become a man, which would include women and children .
Now let's get to the name part if you notice none of Jesus disciples referred to him as Christ, except the one time when Peter said you are the Christ the son of God in Matthew 16:16 .
But that was only one time in 3 and a half year ministry other then that he was always called rabbi or teacher, for he was for filling ,what was spoken about him though the Law and the prophets , even Jesus said the scriptures must be for filled - Matthew 26:54 .
So only a human being could bring mankind back to God.
Now let's get to why Jesus name changed from Jesus to Christ Jesus are you ready to hear it ?
His name changed to Christ Jesus because that was his resurrected name, showing the Messiah in front of The man Jesus .
Because scripture says he was proven to be the Messiah though his rising from the dead read Romans 1: 4.