Some claim ancient pagan holidays form the roots of Christmas and Easter and that God forever ordained the Jewish Feasts. What does the Bible say?
There are seven feasts established in the Mosaic Law (eight, if you include the weekly sabbath). The Feast of Purim was established later by the events recorded in the Book of Esther. The Feasts are a rich part of Jewish culture, and tell a story of God’s redemption and faithfulness. Christians can study many of the details in these feasts and see prophetic meaning fulfilled in the life, sacrifice, and resurrection of Jesus.
Though they are welcome to celebrate Jewish Feast days, Christians are not bound to do so. Acts 15 shows how this this question between Jewish and Gentile followers of Jesus was resolved by the apostles. In the middle of a scathing rebuke of people that insist on religious legalism, Paul had this to say about the Jewish Feasts in Colossians 2:16–17- Therefore let no one pass judgment on you in questions of food and drink, or with regard to a festival or a new moon or a Sabbath. These are a shadow of the things to come, but the substance belongs to Christ.
The New Testament does not record the early church celebrating Christmas or Easter. Their observance was added to church tradition after the canon of scripture was written, but they are not mandated by the Bible. Their alleged links to pagan holidays are not well established and have generally contradictory historical sources. They certainly have been commercialized and diluted of their spiritual meaning by culture.
Paul had this to say about people that feel strongly about reserving particular days to honor God and about those that avoided observing feasts and holidays in 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.