In the gate - Compare the Proverbs 22:22 note.

A fool - openeth not his mouth in the gate - Is not put into public offices of trust and responsibility.

Wisdom [is] too high for a fool: he openeth not his mouth in the (a) gate.
(a) In the place where wisdom should be shown.

Wisdom is too high for a fool,.... It is out of his reach, he cannot attain it; natural wisdom, or the knowledge of many things in nature; at least it seems so to himself, and therefore will not take any pains, or make use of any means, to obtain it; as the knowledge of human laws; of medicine, of philosophy, of languages, or of any of the liberal arts and sciences; or he has not really a capacity for it. This is more especially true of spiritual wisdom, or of the knowledge of divine things in a spiritual way; or of the things Of the Spirit of God, which a natural man cannot know, because they are spiritually discerned; it is God only makes men to know this kind of wisdom in the hidden part, 1-Corinthians 2:14; for as a "fool" here denotes a wicked man, let his natural parts be what they will; so wisdom spiritual knowledge, and experience of divine things, which is too high for an unregenerate man to reach; see a like phrase in Psalm 139:6;
he openeth not his mouth in the gate; he is not qualified far it; and if he has any knowledge of himself, he will not venture to speak in a public assembly, in the house of parliament, in a court of judicature, or in the company of men of knowledge and sense; and indeed it is his highest wisdom to keep silence, and not betray his ignorance: and so with regard to spiritual things; a man that wisdom is too high for, and he has no share of it, shall not or ought not to open his mouth where Wisdom cries; even in the gates of the cities, or in the public assemblies of the saints, Proverbs 1:21.

A weak man thinks wisdom is too high for him, therefore he will take no pains for it. It is bad to do evil, but worse to devise it. Even the first risings of sin in the heart are sin, and must be repented of. Those that strive to make others hateful, make themselves so.

(Compare Proverbs 14:16).
in the gate--(Compare Proverbs 22:22).

Till now in this appendix we have found only two distichs (vid., vol. i. p. 17); now several of them follow. From this, that wisdom is a power which accomplishes great things, it follows that it is of high value, though to the fool it appears all too costly.
7 Wisdom seems to the fool to be an ornamental commodity;
He openeth not his mouth in the gate.
Most interpreters take ראמות for רמות (written as at 1-Chronicles 6:58; cf. Zac 14:10; ראשׁ, Proverbs 10:4; קאם, Hosea 10:14), and translate, as Jerome and Luther: "Wisdom is to the fool too high;" the way to wisdom is to him too long and too steep, the price too costly, and not to be afforded. Certainly this thought does not lie far distant from what the poet would say; but why does he say חכמות, and not חכמה? This חכמות is not a numerical plur., so as to be translated with the Venet.: μετέωροι τῷ ἄφρονι αἱ ἐπιστῆμαι; it is a plur., as Psalm 49:4 shows; but, as is evident from the personification and the construction, Proverbs 1:20, one inwardly multiplying and heightening, which is related to חכמה as science or the contents of knowledge is to knowledge. That this plur. comes here into view as in chap. 1-9 (vid., vol. i. p. 34), is definitely accounted for in these chapters by the circumstance that wisdom was to be designated, which is the mediatrix of all wisdom; here, to be designated in intentional symphony with ראמות, whose plur. ending th shall be for that very reason, however, inalienable. Thus ראמות will be the name of a costly foreign bijouterie, which is mentioned in the Book of Job, where the unfathomableness and inestimableness of wisdom is celebrated; vid., Job 27:18, where we have recorded what we had to say at the time regarding this word. But what is now the meaning of the saying that wisdom is to the fool a pearl or precious coral? Jol Bril explains: "The fool uses the sciences like a precious stone, only for ornament, but he knows not how to utter a word publicly," This is to be rejected, because ראמות is not so usual a trinket or ornament as to serve as an expression of this thought. The third of the comparison lies in the rarity, costliness, unattainableness; the fool despises wisdom, because the expenditure of strength and the sacrifices of all kinds which are necessary to put one into the possession of wisdom deter him from it (Rashi). This is also the sense which the expression has when ראמות = רמות; and probably for the sake of this double meaning the poet chose just this word, and not פנינים, גבישׁ, or any other name, for articles of ornament (Hitzig). The Syr. has incorrectly interpreted this play upon words: sapientia abjecta stulto; and the Targumist: the fool grumbles (מתרעם) against wisdom.
(Note: This explanation is more correct than Levy's: he lifts himself up (boasts) with wisdom.)
He may also find the grapes to be sour because they hang too high for him; here it is only said that wisdom remains at a distance from him because he cannot soar up to its attainment; for that very reason he does not open his mouth in the gate, where the council and the representatives of the people have their seats: he has not the knowledge necessary for being associated in counselling, and thus must keep silent; and this is indeed the most prudent thing he can do.

A fool - For a wicked man, whose sins enfeeble his mind, and make it incapable of wisdom. Openeth not - He knows not how to speak acceptably, and profitably in the publick assembly.