If we celebrate the birth of Christ or his resurrection in honor of God especially on a particular day, we do so for his glory, not our own. Consider Romans 14:5 "One person esteems one day as better than another, while another esteems all days alike. Each one should be fully convinced in his own mind." My conscience is clear on this matter and you wrong your brother by thinking evil of him. Take heed to the verses preceding this passage of Scripture,"Who are you to pass judgment on the servant of another? It is before his own master that he stands or falls. And he will be upheld, for the Lord is able to make him stand."
@James Thomas. I say this out of love: You are mistaken. The law is the righteousness of God and it is good and holy. Wrath comes upon us for disobedience, that is not to say that the law is wrath. Rather wrath is consequence for not fulfilling all righteousness. Christ fulfilled all righteousness for his people and by grace gives us his righteousness. The law was given for transgression to show us our sinfulness and God's utter holiness, which thereby points us to Jesus Christ the Righteous. Read Roman's 6,7, and 8 for a fuller understanding of the purpose of God's law. And also Galatians 3.