The original intent of worshiping within the framework of the church calendar was to guide the believer in his or her spiritual pilgrimage. Its purpose is to relive the life of Christ, to walk in the footsteps of Jesus, to experience what Jesus experienced, to identify with his earthly life, and through that experience, to grow spiritually.
-Robert Webber, Worship Is a Verb: Celebrating God’s Mighty Deeds of Salvation, Second Edition (Peabody, MA: Hendrickson Pub., 1996), 161.
Sabbath–keeping the 7th day of the week holy is an important part of the church calendar.