[T.B. Yoits]

The Son of God was born in a manger in Bethlehem because Joseph and Mary had to return for the census. They couldn't just stay in Nazareth despite the hardship of Mary being pregnant or because Joseph just felt like it.

Christ himself said, "Give to Caesar what is Caesar's...". Clearly the law meant something.

[Nea Wood]

Yes, Joseph and Mary were obeying the law. They were not “illegal aliens” as many try to say. Later, when they went to Egypt, it was because an angel told them to, and they went back home as soon as it was safe.