[De horis canonicis]

...it is not expressly prohibited, rather it is expressly prohibited while the text says and uses this word "suffices," which is imperative, including within itself a prohibition; because what is commanded is ordered, and what is ordered it is necessary to be done, and what is commanded, 1, question 1. For cases of necessity in which he can say more Masses are expressed in law, namely in the said chapters 1 and 2, the chapter Consuluisti and the chapter Ex parte and the chapter Te referente. Therefore, outside those cases, the laws seem to prohibit, because since it is permitted in those cases, therefore in the others it is prohibited, by the argument of the chapter None, on presumption, because if it is conceded in one, it is denied in the other, says the law Cum ita legatum, Digest, on conditions and demonstrations, and the law Cum lex, Digest, on alienation, and thus consequently he sins because he does against a prohibitive law, by the argument of the chapter N, on major and obedience, and also in the text is this word "only," implying also with it a prohibition, by the argument of the chapter Solite, on major and obedience, in the word "only" by the doctors. Think if I say well in your conscience, and when you celebrate, if you celebrate on account of a case of necessity or greed, because God is above all things knowing, and before His tribunal you will have to stand in His tremendous judgment, chapter 1, on re-judicial matters, Book VI. Thus I say on account of some who, here and there, do not fear to celebrate two Masses in a day, not attending that where necessity can be relieved by others, they ought not to celebrate two Masses in a day, as note in the said chapter Consuluisti and in our chapter and other laws allegated above.

I ask further whether the Mass is of the canonical hours. It is answered according to the gloss on the word "fruit of your lips" in the said Clementine 1, on the celebration of Masses, and no, but it is indeed of the offices; and it is inferred that under the appellation of "offices" the Mass is contained, and not under the appellation of "canonical hours." It is clear because bishops, only on account of honesty, are invited to celebrate or hear Masses, chapter final, on privileges, Book VI; but to the canonical hours they are held not only on account of honesty but also...