Ante-Nicene Fathers, Vol III:
Tertullian: Part I: Chapter II.

p. 94 Chapter II.

I affirm that not one of the Faithful has ever a crown upon his head, except at a time of trial. That is the case with all, from catechumens to confessors and martyrs, 385 or (as the case may be) deniers.  Consider, then, whence the custom about which we are now chiefly inquiring got its authority. But when the question is raised why it is observed, it is meanwhile evident that it is observed. Therefore that can neither be regarded as no offence, or an uncertain one, which is perpetrated against a practice which is capable of defence, on the ground even of its repute, and is sufficiently ratified by the support of general acceptance. It is undoubted, so that we ought to inquire into the reason of the thing; but without prejudice to the practice, not for the purpose of overthrowing it, but rather of building it up, that you may all the more carefully observe it, when you are also satisfied as to its reason. But what sort of procedure is it, for one to be bringing into debate a practice, when he has fallen from it, and to be seeking the explanation of his having ever had it, when he has left it off? Since, although he may wish to seem on this account desirous to investigate it, that he may show that he has not done wrong in giving it up, it is evident that he nevertheless transgressed previously in its presumptuous observance.  If he has done no wrong to-day in accepting the crown he offended before in refusing it. This treatise, therefore, will not be for those who not in a proper condition for inquiry, but for those who, with the real desire of getting instruction, bring forward, not a question for debate, but a request for advice. For it is from this desire that a true inquiry always proceeds; and I praise the faith which has believed in the duty of complying with the rule, before it has learned the reason of it. An easy thing it is at once to demand where it is written that we should not be crowned.  But is it written that we should be crowned? Indeed, in urgently demanding the warrant of Scripture in a different side from their own, men prejudge that the support of Scripture ought no less to appear on their part. For if it shall be said that it is lawful to be crowned on this ground, that Scripture does not forbid it, it will as validly be retorted that just on this ground is the crown unlawful, because the Scripture does not enjoin it. What shall discipline do? Shall it accept both things, as if neither were forbidden? Or shall it refuse both, as if neither were enjoined? But “the thing which is not forbidden is freely permitted.” I should rather say 386 that what has not been freely allowed is forbidden.

Footnotes

[Kaye (p. 231) notes this as a rare instance of classing Catechumens among “the Faithful.”]

[This is said not absolutely but in contrast with extreme license; but it shows the Supremacy of Scripture. Compare De Monogam, cap. 4.]