I agree that everything must be supported by Scripture. The best argument against celebrating Christmas is the Regulative Principle which governs all our worship. Unlike sacraments like baptism and the Lord's Supper which we are commanded to observe, we have no such directive to celebrate Christmas. The argument over the meaning of the word Mass is interesting. As the previous poster says, the term "Mass" is derived from the Late Latin word missa (dismissal), used to conclude the Mass with the phrase: "Ite, missa est" ("Go; it is the dismissal"). It has the meaning of 'Mission' Go ye therefore into all the world, teaching all men...' Or from the Anglican communion 'Go in peace to serve the Lord'. I'm not convinced that you can, therefore, interpret the term dismissal out of context in its literal, modern day sense.