At every Mass we attend, the Church reaches back to Calvary and lays hold of the cross of Christ, with Christ on it, and plants it down upon the altar. The Mass is the Holy Sacrifice of Christ on Calvary, present in an unbloody manner, performed by a Catholic priest and participated in by us. It is the highest and central act of worship performed by the Catholic Church. This Sacred Liturgy is the offering to God of Jesus Body and Blood. It is the means by which the merits of His sacrifice upon the cross are applied to us in Holy Communion. The Mass is both Sacrifice and Sacrament.
In the Mass there are three essential acts. In the first act, the
offertory, we offer ourselves along with Christ. We offer adoration,
thanksgiving, contrition, petitions as well as our own crosses, such as
our worries, hardships and pains. In the second act, the Consecration,
we die with Christ, having offered our own sacrifices with Him and dying
to our sins. In the third act, which is the Communion, we rise with
Christ into new life. Having died to the lower order of our sins, we now
rise to the higher order of God’s sanctifying grace.
“Picture then the high priest Christ leaving the sacristy of heaven for the altar of Calvary. He has already put on the vestment of our human nature, the maniple of our suffering, the stole of the priesthood, the chasuble of the Cross. Calvary is his cathedral; the rock of Calvary is the altar stone; the sun turning to red is the sanctuary lamp; Mary and John are the living side altars; the Host is His Body; the wine is His Blood. He is upright as Priest, yet He is prostrate as Victim. His Mass is about to begin.” (From Calvary and the Mass, Fulton Sheen)