Although it doesn't reference holidays, Deuteronomy 11 provides good reasons for having them.
We need constant reminders of God's story.
“Don’t let your heart be deceived so that you turn away from the LORD and serve and worship other gods ... commit yourselves wholeheartedly to these words of mine. Tie them to your hands and wear them on your forehead as reminders. Teach them to your children. Talk about them when you are at home and when you are on the road, when you are going to bed and when you are getting up. Write them on the doorposts of your house and on your gates..."
Holidays are one way we remind ourselves and our children about God's story of love and redemption.
It's not important to know the actual day of Christ's birth,* but it's critically important to remember why His birth changed our lives.
Are you focusing on Christ this Christmas? Ask God to help you "commit yourselves wholeheartedly" to His words and purposes.
*Some Christians don't celebrate Christ's birth on December 25th because they feel historical records show He was born on another day. But the day is not important. If we adopted a child without a known birth date, we would still create a day to celebrate his/her birth because the date is not as important as the person. The same is true for Christ. I prefer to celebrate His birth at the time when most of the world celebrates, others may prefer a date they feel is historically correct. The important thing is that we celebrate!
Why not do a short study on this passage? You'll find it at Bite Size Bible Study.