From the Prayer Book:

The Paschal mystery—the death and resurrection of JesusChrist—is at the heart of the Christian Gospel. The evening ofMaundy Thursday begins the Triduum (the sacred three days).This service, together with Good Friday, Holy Saturday, andThe Great Vigil of Easter, form a single liturgy; thus, the final blessing and dismissal is reserved for the conclusion of theGreat Vigil.Maundy Thursday receives its name from the mandatum (commandment) given by our Lord: “A new commandmentI give to you, that you love one another: just as I have loved you, you also are to love one another” (john 13:34). At theLast Supper, Jesus washed his disciples’ feet and commanded them to love and serve one another as he had done. This day commemorates the Lord’s example of servant ministry, the institution of the Eucharist, the agony in the Garden ofGethsemane, and the betrayal leading to the crucifixion.