This is probably one of the most merry moments of the whole year even in the secular sense: people have vacations at the end of the year.
And there have been a lot of debates whether Christians should celebrate Christmas because of its spectacular pagan origin. (Note that there is a similar argument against Halloween.) However, I would still celebrate it. R. C. Sproul wrote in his blog yesterday:
“I can’t think of anything more pleasing to Christ than the church celebrating His birthday every year… I certainly see nothing wrong with the church’s entering into this joyous time of celebrating the Incarnation, which is the dividing point of all human history. Originally, it was intended to honor, not Mithras or any of the other mystery religion cults, but the birth of our King.”
And what about Santa Claus? It is in memory of St. Nicholas too. The tradition of Santa Claus went through the Catholic Church in the Medieval Times, and Reformation, as Stephen Nichols wrote in his blog.
Jesus was born humbly in a manger, but to be a prophet, a priest, and a king.
 “The LORD your God will raise up for you a prophet like me from among you, from your brothers—it is to him you shall listen— just as you desired of the LORD your God at Horeb on the day of the assembly, when you said, ‘Let me not hear again the voice of the LORD my God or see this great fire any more, lest I die.’  And the LORD said to me, ‘They are right in what they have spoken.  I will raise up for them a prophet like you from among their brothers. And I will put my words in his mouth, and he shall speak to them all that I command him. (Deuteronomy 18:15-18 ESV)
 The LORD has sworn and will not change his mind, “You are a priest forever after the order of Melchizedek.” (Psalm 110:4 ESV)
 For to us a child is born, to us a son is given; and the government shall be upon his shoulder, and his name shall be called Wonderful Counselor, Mighty God, Everlasting Father, Prince of Peace.  Of the increase of his government and of peace there will be no end, on the throne of David and over his kingdom, to establish it and to uphold it with justice and with righteousness from this time forth and forevermore. The zeal of the LORD of hosts will do this. (Isaiah 9:6-7 ESV)
- “37 Cats Crashing Nativity Scenes,” Ranker. [link]
- R. C. Sproul, “Is Christmas a Pagan Holiday?” Ligonier Ministries (Dec 2015). [link]
- S. Nichols, “Saint Nicholas and the Origins of Santa Claus,” Ligonier Ministries (Dec 2015). [link]