Roman Catechism 18.52

Chapter 18 — Part II: The Sacraments — The Holy Eucharist

Section 52. Form To Be Used In The Consecration Of The Wine — With regard lo the consecration of the wine, which is the other element of this Sacrament, the priest, for the reason we have already assigned, ought of necessity to be well acquainted with, and well understand its form. We are then firmly to believe that it consists in the following words: This is the chalice of my blood, of the new and eternal testament, the mystery of faith, which shall be shed for you and for many, to the remission of sins. Of these words the greater part are taken from Scripture; but some have been preserved in the Church from Apostolic tradition.