In one sense, there's nothing special about "Holy Week." Just another sequence of eight days each spring — nothing is intrinsically holy about this Sunday to Sunday that moves around the calendar each year. We have no mandate from Jesus or his apostles to mark these days for particular observance. Paul, for one, would be quite happy for us to partake, or not. "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" (Romans 14:5).
Clearly, the celebration should not be pressed upon the conscience of others. "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" (Colossians 2:16).
Opportunity, Not Obligation
Celebrating Holy Week is not an obligation, but it is an opportunity. It is a chance to walk with the church, throughout time and throughout the world, as she walks with her Bridegroom through the most important week in the history of the world. It is a chance to focus our minds on, and seek to intensify our affections for, the most important and timeless of realities.
While not mandating the observance, or even suggesting it, the New Testament does give us indirect reason, if we're looking for it. The final eight of Matthew's 28 chapters are given to this one week, along with the last six of Mark’s sixteen and the final six of Luke's 24.
Most significant, though, is John. Ten of the Gospel's 21 chapters — essentially half — deal with the final week of our Lord's life, his betrayal, his trials, his crucifixion, and his triumphant resurrection. Even Acts, which then narrates the life of the early church, returns to the events of Holy Week with frequency (see, for instance, Acts 1:15–19; 2:22–36; 3:11–26; 4:8–12, 24–28, among others).
Indeed, it could even be said that all the Old Testament anticipates this week, and the rest of the New Testament reflects it in theology and practical living.