The most direct proverb, in the sense of "similitude," which has as yet met us.
Jewel of gold - Better, ring; i. e., the nose-ring Genesis 24:22, Genesis 24:47; Isaiah 3:21.
Without discretion - literally, "without taste," void of the subtle tact and grace, without which mere outward beauty is as ill-bestowed as the nose-ring in the snout of the unclean beast. If we may assume that in ancient Syria, as in modern Europe, swine commonly wore such a ring to hinder them doing mischief, the similitude receives a fresh vividness.

A jewel of gold in a swine's snout - That is, beauty in a woman destitute of good breeding and modest carriage, is as becoming as a gold ring on the snout of a swine. Coverdale translates thus: "A fayre woman without discrete maners, is like a ringe of golde in a swyne's snoute." In Asiatic countries the nose jewel is very common: to this the text alludes.

As a jewel of gold in a swine's snout,.... The allusion seems to be to the ringing of swine, to prevent their rooting up the earth; which is usually done by putting an iron ring into their snout; which is much more proper and suitable than a gold ring, or a jewel set in gold, which is very unbecoming such a creature; and is soon had to the dunghill, or to some miry place, and there defiled;
so is a fair woman which is without discretion; or, "has departed from taste" (y); from a taste of virtue and honour; lost all sense of modesty and chastity; forsaken her husband, and given up herself to the embraces of others. As her beauty is fitly expressed by a "jewel of gold", which is valuable and desirable, and, rightly placed and used, is ornamental; so she is properly represented by a swine, wallowing in the impurities of lust; to which her beauty was the snare, and whereby it is quickly sullied and lost. Jarchi applies this to a disciple of a wise man, or a scholar that departs from the good way, or from the law; which he explains by taste or sense: but it may be better applied to the scarlet whore, or apostate church of Rome; which has departed from Christ, once her professed husband; from the doctrines of the Gospel, and the ordinances of it; from all taste and savour of true religion; and even from common sense and right reason, as in the affair of transubstantiation, and other things; and may be fitly compared to a swine with a jewel of gold in its snout, being "decked with gold, and precious stones, and pearls"; and yet "drunk with the blood of the saints", and "martyrs of Jesus"; and wallowing in all the faith of fornication, of idolatry, and superstition; as well as in all manner of other sins and iniquities, Revelation 17:4.
(y) Hebrews. "recedens a gusta", Piscator; "cujus recessit sapor", Schultens.

Beauty is abused by those who have not discretion or modesty with it. This is true of all bodily endowments.

Jewels were often suspended from the nose (Genesis 24:47; Isaiah 3:21). Thus adorned, a hog disgusts less than a fair and indiscreet woman.

22 A golden ring in a swine's snout -
A fair woman and without delicacy.
This is the first instance of an emblematical proverb in which the first and second lines are related to each other as figure and its import, vid., p. 9. The lxx translates rhythmically, but by its ὥσπερ οὕτως it destroys the character of this picture-book proverbial form. The nose-ring, נזם, generally attached to the right nostril and hanging down over the mouth (vid., Lane's Manners, etc.) is a female ornament that has been in use since the time of the patriarchs (Genesis 24:47). If one supposes such a ring in a swine's snout, then in such a thing he has the emblem of a wife in whom beauty and the want of culture are placed together in direct contrast. טעם is taste carried over into the intellectual region, the capability of forming a judgment, Job 12:20, and particularly the capability of discovering that which is right and adapted to the end in view, 1-Samuel 25:33 (of Abigail), here in accordance with the figure of a beast with which the ideas of uncleanness, shamelessness, and rudeness are associated, a mind for the noble, the fine, the fitting, that which in the higher and at the same time intellectual and ethical sense we call tact (fine feeling); סרת (alienata) denotes the want of this capacity, not without the accompanying idea of self-guilt.

So is a fair woman without discretion -
"Of beauty vain, of virtue void, What art thou in the sight of God? A slave to every base desire, A creature wallowing in the mire. Go, gaudy pageant of a day, Thy folly, with thy face display: Set all thy charms and graces out, And shew - the Jewel in thy snout!"