“The Reformed tradition, because of its application of the regulative principle of worship, opposed the celebration of any other day than the Sabbath as a required assembly for church members. The regulative principle teaches succinctly that the church, corporately conceived, may require only what finds clear and explicit warrant in God’s Word. The church calendar, accordingly, may be a thoughtful way to remind believers that the way they mark time is different from that of the world. But because the calendar lacks a clear warrant from Scripture, older generations of Presbyterians rejected it as a human invention, no matter how wise or venerable, and therefore illegitimate for the church as a body. Individuals may observe certain holy days, but church officers can require observance only of the one holy day countenanced in the New Testament, namely, the Lord’s Day.
“High-church Presbyterianism does not reject the church calendar as much as it offers an alternative, one that revolves around the week-in and week-out observance of the Sabbath. Reformed Protestants, then, have fifty-two holy days a year. On these sacred days, when Christians rest from their weekly labors and gather for worship, they not only follow the pattern of days God established in the creation week but also look forward to the sabbath rest that awaits all God’s children when Christ returns. This is especially true in worship itself when, as Reformed believe, the church gathers spiritually on the Lord’s Day with the rest of the saints and angels in the presence of Christ to perform those acts of worship and service that prefigure the marriage supper of the Lamb.”
(D.G. Hart, Recovering Mother Kirk: The Case for Liturgy in the Reformed Tradition, 31-32.)