Two major themes of the bible: promise and fulfillment. 

Therefore the Lord himself will give you a sign: The virgin will conceive and give birth to a son, and will call him Immanuel.

Isaiah 7:14

“But you, Bethlehem Ephrathah, though you are small among the clans of Judah, out of you will come for me one who will be ruler over Israel, whose origins are from of old, from ancient times.”

Micah 5:2

God is at work. 

2 Peter 3, The Lord is not slow in keeping his promise, as some understand slowness. He is patient…

In those days Caesar Augustus issued a decree that a census should be taken of the entire Roman world. 2 (This was the first census that took place while Quirinius was governor of Syria.) 3 And everyone went to their own town to register.

Luke 2:1-3

1. God is at work through unjust government.

So Joseph also went up from the town of Nazareth in Galilee to Judea, to Bethlehem the town of David, because he belonged to the house and line of David. 5 He went there to register with Mary, who was pledged to be married to him and was expecting a child.

Luke 2:4-5

2. God is at work through difficulties.

While they were there, the time came for the baby to be born, 7 and she gave birth to her firstborn, a son. She wrapped him in cloths and placed him in a manger, because there was no guest room available for them.

Luke 2:6-7

3. God is at work always at the right time

While they were there, the time came for the baby to be born…

Luke 2:6

For we do not have a high priest who is unable to empathize with our weaknesses, but we have one who has been tempted in every way, just as we are—yet he did not sin. 16 Let us then approach God’s throne of grace with confidence, so that we may receive mercy and find grace to help us in our time of need.

Hebrews 4:15-16

…and she gave birth to her firstborn, a son. She wrapped him in cloths and placed him in a manger, because there was no guest room available for them.

Luke 2:6-7

Holy, holy, holy is the LORD Almighty; the whole earth is full of his glory.” 

Isaiah 6:3