From the 1965 encyclical Mysterium Fidei by Pope Paul VI:
23. . . . Once the integrity of the faith has been safeguarded, then it is time to guard the proper way of expressing it, lest our careless use of words give rise, God forbid, to false opinions regarding faith in the most sublime things. St. Augustine gives a stern warning about this when he takes up the matter of the different ways of speaking that are employed by the philosophers on the one hand and that ought to be used by Christians on the other. “The philosophers,” he says, “use words freely, and they have no fear of offending religious listeners in dealing with subjects that are difficult to understand. But we have to speak in accordance with a fixed rule, so that a lack of restraint in speech on our part may not give rise to some irreverent opinion about the things represented by the words” [Augustine, Bishop of Hippo, City of God, X, 23].
24. And so the rule of language which the Church has established through the long labor of centuries, with the help of the Holy Spirit, and which she has confirmed with the authority of the Councils, and which has more than once been the watchword and banner of orthodox faith, is to be religiously preserved, and no one may presume to change it at his own pleasure or under the pretext of new knowledge. Who would ever tolerate that the dogmatic formulas used by the ecumenical councils for the mysteries of the Holy Trinity and the Incarnation be judged as no longer appropriate for men of our times, and let others be rashly substituted for them? In the same way, it cannot be tolerated that any individual should on his own authority take something away from the formulas which were used by the Council of Trent to propose the Eucharistic Mystery for our belief. These formulas—like the others that the Church used to propose the dogmas of faith—express concepts that are not tied to a certain specific form of human culture, or to a certain level of scientific progress, or to one or another theological school. Instead they set forth what the human mind grasps of reality through necessary and universal experience and what it expresses in apt and exact words, whether it be in ordinary or more refined language. For this reason, these formulas are adapted to all men of all times and all places.
25. They can, it is true, be made clearer and more obvious; and doing this is of great benefit. But it must always be done in such a way that they retain the meaning in which they have been used, so that with the advance of an understanding of the faith, the truth of faith will remain unchanged. For it is the teaching of the First Vatican Council that “the meaning that Holy Mother the Church has once declared, is to be retained forever, and no pretext of deeper understanding ever justifies any deviation from that meaning” [Vatican Council I, Dogmatic Constitution on the Catholic Faith, 4].