Holy Thursday

With this Mass, celebrated in the evening of the Thursday inHoly Week, the Church begins the sacred Easter Triduum and devotes herself tothe remembrance of the Last Supper.

At the supper on the night he was betrayed, the Lord Jesus,loving those who were his own in the world even to the end, knelt to wash hisapostles’ feet, the work of a servant. For a last time he demonstrated that weare here to serve one another.

He then offered his Body and Blood to the Father under theappearance of bread and wine, gave them to the apostles to eat and drink, thenenjoined the apostles and their successors in the priesthood to offer them inturn. So this Mass is, first of all, the memorial of the institution of theEucharist, that is, of the Memorial of the Lord’s Passover, by which undersacramental signs he perpetuated among us the sacrifice of the New Law. TheMass of the Lord’s Supper is also the memorial of the institution of thepriesthood, by which Christ’s mission and sacrifice are perpetuated in theworld. And finally, this Mass is the memorial of that love by which the Lordloved us even to death.

(from http://www.usccb.org/prayer-and-worship/liturgical-year/triduum/roman-missal-and-the-evening-mass-of-the-lords-supper.cfm)