Luke 2:1 And it came to pass in those days, that there went out a decree from Caesar Augustus, that all the world should be taxed.
Have you ever wondered why some things happen in life? What would possess Caesar Augustus to do something so labour intensive as to count everyone in the land?
The logistics and money involved in making this all happen would frighten most people into not doing anything like this to start with.
What else would have motivated Mary and Joseph to get up and go to the City of David just as was predicted by the prophets of old?
God uses all people to make sure His will in done at the right time and the right place; just open your eyes and believe!