Objection 1. It would seem that all are equally bound to have explicit faith. For all are bound to those things which are necessary for salvation, as is evidenced by the precepts of charity. Now it is necessary for salvation that certain things should be believed explicitly. Therefore all are equally bound to have explicit faith.
Objection 2. Further, no one should be put to test in matters that he is not bound to believe. But simple reasons are sometimes tested in reference to the slightest articles of faith. Therefore all are bound to believe everything explicitly.
Objection 3. Further, if the simple are bound to have, not explicit but only implicit faith, their faith must needs be implied in the faith of the learned. But this seems unsafe, since it is possible for the learned to err. Therefore it seems that the simple should also have explicit faith; so that all are, therefore, equally bound to have explicit faith.
On the contrary, It is written (Job 1:14): "The oxen were ploughing, and the asses feeding beside them," because, as Gregory expounds this passage (Moral. ii, 17), the simple, who are signified by the asses, ought, in matters of faith, to stay by the learned, who are denoted by the oxen.
I answer that, The unfolding of matters of faith is the result of Divine revelation: for matters of faith surpass natural reason. Now Divine revelation reaches those of lower degree through those who are over them, in a certain order; to men, for instance, through the angels, and to the lower angels through the higher, as Dionysius explains (Coel. Hier. iv, vii). On like manner therefore the unfolding of faith must needs reach men of lower degree through those of higher degree. Consequently, just as the higher angels, who enlighten those who are below them, have a fuller knowledge of Divine things than the lower angels, as Dionysius states (Coel. Hier. xii), so too, men of higher degree, whose business it is to teach others, are under obligation to have fuller knowledge of matters of faith, and to believe them more explicitly.
Reply to Objection 1. The unfolding of the articles of faith is not equally necessary for the salvation of all, since those of higher degree, whose duty it is to teach others, are bound to believe explicitly more things than others are.
Reply to Objection 2. Simple persons should not be put to the test about subtle questions of faith, unless they be suspected of having been corrupted by heretics, who are wont to corrupt the faith of simple people in such questions. If, however, it is found that they are free from obstinacy in their heterodox sentiments, and that it is due to their simplicity, it is no fault of theirs.
Reply to Objection 3. The simple have no faith implied in that of the learned, except in so far as the latter adhere to the Divine teaching. Hence the Apostle says (1 Corinthians 4:16): "Be ye followers of me, as I also am of Christ." Hence it is not human knowledge, but the Divine truth that is the rule of faith: and if any of the learned stray from this rule, he does not harm the faith of the simple ones, who think that the learned believe aright; unless the simple hold obstinately to their individual errors, against the faith of the universal Church, which cannot err, since Our Lord said (Luke 22:32): "I have prayed for thee," Peter, "that thy faith fail not."
Source: Summa Theologica (New Advent)