Holy Thursday is the commemoration of the Last Supper of Jesus Christ, when he established the sacrament of Holy Communion prior to his arrest and crucifixion. It also commemorates His institution of the priesthood. The holy day falls on the Thursday before Easter and is part of Holy Week. Jesus celebrated the dinner as a Passover feast. Christ would fulfill His role as the Christian victim of the Passover for all to be saved by His final sacrifice.
The Last Supper was the final meal Jesus shared with his Disciples in Jerusalem. During the meal, Jesus predicts his betrayal.The central observance of Holy Thursday is the ritual reenactment of the Last Supper at Mass. This event is celebrated at every Mass, as party of the Liturgy of the Eucharist, but it is specially commemorated on Holy Thursday.
He also establishes the special priesthood for his disciples, which is distinct from the "priesthood of all believers." Christ washed the feet of his Disciples, who would become the first priests. Out of love and with humility, he placed himself in service to others. So too we are called to serve one another. As often as we eat this bread and drink this cup, let us remember what Jesus did at the Last Supper and go and do the same. The Holy Thursday Gospel reading can be found in the book of John 13:1-15.