Judge in yourselves - Or, "Judge among yourselves." I appeal to you. I appeal to your natural sense of what is proper and right. Paul had used various arguments to show them the impropriety of their females speaking unveiled in public. He now appeals to their natural sense of what was decent and right, according to established and acknowledged customs and habits.
Is it comely - Is it decent, or becoming? The Grecian women, except their priestesses, were accustomed to appear in public with a veil - Doddridge. Paul alludes to that established and proper habit, and asks whether it does not accord with their own views of propriety that women in Christian assemblies should also wear the same symbol of modesty.

Judge in yourselves - Consider the subject in your own common sense, and then say whether it be decent for a woman to pray in public without a veil on her head? The heathen priestesses prayed or delivered their oracles bare-headed or with dishevelled hair, non comptae mansere comae, as in the case of the Cumaean Sibyl, Aen. vi., ver. 48, and otherwise in great disorder: to be conformed to them would be very disgraceful to Christian women. And in reference to such things as these, the apostle appeals to their sense of honor and decency.

(12) Judge in yourselves: is it comely that a woman pray unto God uncovered?
(12) He urges the argument taken from the common sense of nature.

Judge in yourselves,.... The apostle having gone through a variety of reasoning and arguments, showing the superiority of the man to the woman, by which he would prove, that the one should be covered, and the other uncovered, returns to his subject again, and appeals to the common sense and understanding of the Corinthians, and makes them themselves judges of the matter; suggesting that the thing was so clear, and he so certain of what he had advanced being right, that he leaves it with them, not doubting but that they would, upon a little reflection within themselves, join with him in this point:
is it comely that a woman pray unto God uncovered? in you judgment you can never think so, however pleasing and gratifying such a sight may be, to the lust of the flesh, and to the lust of the eye; he does not mention prophesying, only instances in praying; but it is to be understood of one, as of another; and his meaning is, that it is an uncomely thing in a woman to appear in public service with her head uncovered, whether it be in joining in the public prayers, or in singing of psalms, or in hearing the word expounded; and though the apostle does not put the case of the man's praying to God, or prophesying in his name with his head covered, yet his sense is the same of that, as of the woman's.

Appeal to their own sense of decorum.
a woman . . . unto God--By rejecting the emblem of subjection (the head-covering), she passes at one leap in praying publicly beyond both the man and angels [BENGEL].

Is it comely that a woman should pray, etc.? That is, in the public assembly. Private prayer, or with her own sex or household, is not meant. It was very unbecoming in view of the customs of the East, nor would it generally be esteemed decorous in our times, and with our ideas, that she should appear with no covering on her head at all.
Doth not even nature itself, etc.? It is nature's arrangement that men should wear short hair, and a woman long. For a man to have long hair and a woman to be shorn are violations of nature's teachings.
But if a man seem to be contentious. If, in spite of nature's lessons, a man contentiously opposes, let him know that no such custom exists in the churches. Many suppose that custom refers to being contentious. I think, rather, that it refers to covering the head, etc. The lesson of this whole passage is that we must not defy existing social usages in such a way as to bring reproach on the church.

Judge of yourselves - For what need of more arguments if so plain a case? Is it decent for a woman to pray to God - The Most High, with that bold and undaunted air which she must have, when, contrary to universal custom, she appears in public with her head uncovered?