Jesus came to earth to establish his Kingdom in our hearts

4 And Joseph also went up from Galilee, from the town of Nazareth, to Judea, to the city of David, which is called Bethlehem, because he was of the house and lineage of David, 5 to be registered with Mary, his betrothed, who was with child. 6 And while they were there, the time came for her to give birth. 7 And she gave birth to her firstborn son and wrapped him in swaddling cloths and laid him in a manger, because there was no place for them in the inn.
Luke 2:4-7

28 Come to me, all who labor and are heavy laden, and I will give you rest.** 29** Take my yoke upon you, and learn from me, for I am gentle and lowly in heart, and you will find rest for your souls. 30 For my yoke is easy, and my burden is light.
Matthew 11:28-30

8 And in the same region there were shepherds out in the field, keeping watch over their flock by night. 9 And an angel of the Lord appeared to them, and the glory of the Lord shone around them, and they were filled with great fear.10 And the angel said to them, “Fear not, for behold, I bring you good news of great joy that will be for all the people.11 For unto you is born this day in the city of David a Savior, who is Christ the Lord. 12 And this will be a sign for you: you will find a baby wrapped in swaddling cloths and lying in a manger.” 13 And suddenly there was with the angel a multitude of the heavenly host praising God and saying,14 “Glory to God in the highest, and on earth peace among those with whom he is pleased!”
Luke 2:8-14

Christmas reminds us there is always a reason for joy