Council of Trent
DOCTRINE ON THESACRIFICE OF THE MASS
On the Canon of the Mass.
And whereas it beseemeth, that holy things be administered in a holy manner, and of all holy things this sacrifice is the most holy; to the end that it might be worthily and reverently offered and received, the Catholic Church instituted, many years ago, the sacred Canon, so pure from every error, that nothing is contained therein which does not in the highest degree savour of a certain holiness and piety, and raise up unto God the minds of those that offer. For it is composed, out of the very words of the Lord, the traditions of the apostles, and the pious institutions also of holy pontiffs.
On not celebrating the Mass every where in the vulgar tongue; the mysteries of the Mass to be explained to the people.
Although the mass contains great instruction for the faithful people, nevertheless, it has not seemed expedient to the Fathers, that it should be every where celebrated in the vulgar tongue. Wherefore, the ancient usage of each church, and the rite approved of by the holy Roman Church, the mother and mistress of all churches, being in each place retained; and, that the sheep of Christ may not suffer hunger, nor the little ones ask for bread, and there be none to break it unto them, the holy Synod charges pastors, and all who have the cure of souls, that they frequently, during the celebration of mass, expound either by themselves, or others, some portion of those things which are read at mass, and that, amongst the rest, they explain some mystery of this most holy sacrifice, especially on the Lord's days and festivals.
CANON VI.--If any one saith, that the canon of the mass contains errors, and is therefore to be abrogated; let him be anathema.
CANON IX.--If any one saith, that the rite of the Roman Church, according to which a part of the canon and the words of consecration are pronounced in a low tone, is to be condemned; or, that the mass ought to be celebrated in the vulgar tongue only; or, that water ought not to be mixed with the wine that is to be offered in the chalice, for that it is contrary to the institution of Christ; let him be anathema.