Tertullian, Ad Nationes, Book I Chapter III - The Great Offence in the Christians Lies in Their Very Name. The Name Vindicated.
Since, therefore, you who are in other cases most scrupulous and persevering in investigating charges of far less serious import, relinquish your care in cases like ours, which are so horrible, and of such surpassing sin that impiety is too mild a word for them, by declining to hear confession, which should always be an important process for those who conduct judicial proceedings; and failing to make a full inquiry, which should be gone into by such as sue for a condemnation, it becomes evident that the crime laid to our charge consists not of any sinful conduct, but lies wholly in our name. If, indeed, any real crimes were clearly adducible against us, their very names would condemn us, if found applicable, so that distinct sentences would be pronounced against us in this wise: Let that murderer, or that incestuous criminal, or whatever it be that we are charged with, be led to execution, be crucified, or be thrown to the beasts. Your sentences, however, import only that one has confessed himself a Christian. No name of a crime stands against us, but only the crime of a name. Now this in very deed is neither more nor less than the entire odium which is felt against us. The name is the cause: some mysterious force intensified by your ignorance assails it, so that you do not wish to know for certain that which for certain you are sure you know nothing of; and therefore, further, you do not believe things which are not submitted to proof, and, lest they should be easily refuted, you refuse to make inquiry, so that the odious name is punished under the presumption of (real) crimes. In order, therefore, that the issue may be withdrawn from the offensive name, we are compelled to deny it; then upon our denial we are acquitted, with an entire absolution for the past: we are no longer murderers, no longer incestuous, because we have lost that name. But since this point is dealt with in a place of its own, do you tell us plainly why you are pursuing this name even to extirpation? What crime, what offence, what fault is there in a name? For you are barred by the rule which puts it out of your power to allege crimes (of any man), which no legal action moots, no indictment specifies, no sentence enumerates. In any case which is submitted to the judge, inquired into against the defendant, responded to by him or denied, and cited from the bench, I acknowledge a legal charge. Concerning, then, the merit of a name, whatever offence names may be charged with, whatever impeachment words may be amenable to, I for my part think, that not even a complaint is due to a word or a name, unless indeed it has a barbarous sound, or smacks of ill-luck, or is immodest, or is indecorous for the speaker, or unpleasant to the hearer. These crimes in (mere) words and names are just like barbarous words and phrases, which have their fault, and their solecism, and their absurdity of figure. The name Christian, however, so far as its meaning goes, bears the sense of anointing. Even when by a faulty pronunciation you call us “Chrestians” (for you are not certain about even the sound of this noted name), you in fact lisp out the sense of pleasantness and goodness. You are therefore vilifying in harmless men even the harmless name we bear, which is not inconvenient for the tongue, nor harsh to the ear, nor injurious to a single being, nor rude for our country, being a good Greek word, as many others also are, and pleasant in sound and sense. Surely, surely, names are not things which deserve punishment by the sword, or the cross, or the beasts.
Justin Martyr, The First Apology of Justin, Chapter IV - Christians Unjustly Condemned for Their Mere Name.
By the mere application of a name, nothing is decided, either good or evil, apart from the actions implied in the name; and indeed, so far at least as one may judge from the name we are accused of, we are most excellent people. But as we do not think it just to beg to be acquitted on account of the name, if we be convicted as evil-doers, so, on the other hand, if we be found to have committed no offence, either in the matter of thus naming ourselves, or of our conduct as citizens, it is your part very earnestly to guard against incurring just punishment, by unjustly punishing those who are not convicted. For from a name neither praise nor punishment could reasonably spring, unless something excellent or base in action be proved. And those among yourselves who are accused you do not punish before they are convicted; but in our case you receive the name as proof against us, and this although, so far as the name goes, you ought rather to punish our accusers. For we are accused of being Christians, and to hate what is excellent (Chrestian) is unjust. Again, if any of the accused deny the name, and say that he is not a Christian, you acquit him, as having no evidence against him as a wrong-doer; but if any one acknowledge that he is a Christian, you punish him on account of this acknowledgment. Justice requires that you inquire into the life both of him who confesses and of him who denies, that by his deeds it may be apparent what kind of man each is. For as some who have been taught by the Master, Christ, not to deny Him, give encouragement to others when they are put to the question, so in all probability do those who lead wicked lives give occasion to those who, without consideration, take upon them to accuse all the Christians of impiety and wickedness. And this also is not right. For of philosophy, too, some assume the name and the garb who do nothing worthy of their profession; and you are well aware, that those of the ancients whose opinions and teachings were quite diverse, are yet all called by the one name of philosophers. And of these some taught atheism; and the poets who have flourished among you raise a laugh out of the uncleanness of Jupiter with his own children. And those who now adopt such instruction are not restrained by you; but, on the contrary, you bestow prizes and honours upon those who euphoniously insult the gods.