The Triduum Sacrum, or the “Three Sacred Days,” are Maundy Thursday, Good Friday, and The Easter Vigil. For the Church, these three services are observed as one extended Service. The history of the Triduum Sacrum is significant and unites the Christian with the rich liturgical worship of the Church of the ages in her holiest time.
The Divine Service on Maundy Thursday is the service of the Institution of the Sacrament of the Altar, celebrated in the evening. This Service of the Institution begins with the Invocation, but there is no Benediction. The word “Maundy” comes from an older word that means “command.” It is derived from the Latin mandatum novum, “a new command,” our Lord’s Words in St. John 13.34. On this night, Thursday night of Holy Week, our Lord instituted the Sacrament of the Altar. Our Lord’s suffering in the garden, His betrayal and arrest followed (see St. Matthew 26.17-75). The strong connections between the Passover meal and the Institution of the Sacrament of the Altar provide an important setting for Maundy Thursday.
While the Gospel of St. John does not include an account of the Institution of the Sacrament of the Altar as do the other Gospel accounts, the “High Priestly Prayer” that Jesus prayed in the upper room before His betrayal and arrest, is found only in St. John (13.31-18.26). At the end of the Maundy Thursday Divine Service, the altar is stripped, representing the stripping, humiliation and torture of our Lord. During the stripping of the altar, Psalm 22 is chanted while the congregation sits in silence.