December 25th was indeed a pagan holiday. In ancient ages many new converts yielded to temptation to keep that feast. It seems that Christian leaders endeavored to counteract that practice by giving believers a Christian festival on the same day, celebrating the birth of Christ. Some churches in our day conduct special banquets or other attractions for their high school seniors on the night of the senior prom for much the same motive. Certainly the celebration of Christmas is not a continuation of the pagan holiday. It is a unique Christian observance hailing the birth of Jesus Christ.
Moreover, December 25 is especially fitting in that it comes four days after the winter solstice. As the days grow longer with more light, Christians rejoice in the hope of the world in the birth of him who called himself the Light of the World. G. H. Montgomery wrote, “Church leaders saw in the birth of Jesus a triumph of light over darkness, spring over winter and of life over death. What more appropriate time could have been selected to commemorate the birth of the Man whose life, teachings and vicarious death were to change the trends of history, cause light to shine out of darkness and offer light to those who dwell in the valley of death! It will be good to keep these things in mind as you observe Christmas.”
God isn’t against Christmas. God is in favor of Christmas—of the proper observance of the holiday, that is. God planned and executed the first Christmas. No matter how flagrantly men may abuse this holiday, they cannot rob devout believers of its wonder and glory as expressed by the angel of old, “Fear not: for, behold, I bring you good tidings of great joy, which shall be to all people. For unto you is born this day in the city of David a Savior, which is Christ the Lord” (Luke 2:10, 11).
Ref# Raymond L. Cox., Answers In Action.