Your Protestant church probably doesn't observe the church calendar that marks such events as Epiphany and Pentecost. You might even regard this structure as legalistic, subversive of the true gospel of grace.

But make no mistake: you follow some calendar. It might be the school year, based on the agricultural seasons of planting, growing, and harvesting. Or it might be the so-called Hallmark Church Calendar: Valentine's Day, Mother's Day, Fathers's Day, Fourth of July, Veterans Day, and so on. The same goes for our liturgy. Every church has a liturgy. The only question is whether it's edifying and biblical.