Holy Thursday is above all the commemoration of Christ's institution of the Eucharist at the Last Supper with his faithful apostles. In his first Encyclical John Paul II emphasized the centrality of the Eucharist to the life of the Church and of the People of God of the New Covenant in his Blood. (It is an essential truth, not only of doctrine but also of life, that the Eucharist builds the Church, building it as the authentic People of God, as the assembly of the faithful...... ever building and regenerating it on the basis of the Sacrifice of Christ, since it commemorates his death on the Cross, the price by which he redeemed us. In the Eucharist we touch in a way the very mystery of the Body and Blood of the Lord. Encyclical "Redeemer of Man, n. 20") He returned to this same topic in his last Encyclical, "The Church Lives by the Eucharist."
In the two solemn liturgies of Holy Thursday (the Chrism Mass and the Mass of the Lord's Supper) the Church celebrates the deeper understanding, to which she has been led under the light of the Holy Spirit, of some of the mysteries contained in Jesus' passion, death and resurrection. Jesus' intention was that the commemoration of his last supper should be a living memorial of his expiatory sacrifice on the Cross the following day; that the apostles who had received the command "Do this in memory of me," should not only fulfill this charge themselves but hand it on to others whom they might choose, thus giving rise to the sacrament of Holy Orders of Bishop and Priest. The evening liturgy highlights as well that the whole community of those who believe in him should be enlivened by a spirit of self-giving and sacrifice, imitating his example.
These truths that the Church teaches these days reflect the new-found appreciation for the Sacred Scriptures and for the contribution of generations of saints, whom we refer to as Fathers of the Church, whose reflections on the Word of God and the Life of God's Holy People, enriched her life in the early centuries were brought to the contemporary Church by the Second Vatican Council.