This emphatic reproduction of the old rule of Deuteronomy 25:13-14 is perhaps a trace of the danger of dishonesty incidental to the growing commerce of the Israelites. The stress laid upon the same sin in Proverbs 16:11; Proverbs 20:10; bears witness to the desire of the teacher to educate the youth of Israel to a high standard of integrity, just as the protest of Hosea against it Hosea 12:7 shows the zeal of the prophet in rebuking what was becoming more and more a besetting sin.
A just weight - literally, as in the margin, indicating a time when stones rather than metal were used as a standard of weight. Compare Deuteronomy 25:13.

A false balance is abomination - This refers to the balance itself deceitfully constructed, so that it is sooner turned at one end than at the other. This is occasioned by one end of the beam being longer than the other.
But a just weight - אבן שלמה eben shelemah, the perfect stone probably because weights were first made of stone; see the law, Deuteronomy 25:13-16 (note).

A false (a) balance [is] abomination to the LORD: but a just weight [is] his delight.
(a) Under this word he condemns all false weights, measures and deceit.

A false balance is abomination to the Lord,.... Under which are included all false weights and measures, and all fraudulent practices in commerce and dealing; which are forbidden by the Lord, and are abominable to him, as being injurious to the estates and properties of men: and more especially must be abominable in professors of religion, as being contrary to the grace of God; for though there may be common honesty where there is not the grace of God, yet there cannot be the true grace of God where there is not honesty; for the grace of God teaches to deny all such worldly lusts;
but a just weight is his delight; or a "perfect stone" (c); the ancient practice being to make use of stones for weights; Now to give just weight, and also just measure, and to do justly in all civil dealings with men, is what God requires, and is well pleasing in his sight (d); see Leviticus 19:35. This may be understood of balances and weights in religious affairs; the balance of the sanctuary is the word of God, with which all doctrines are to be weighed, and, if found wanting, they are to be rejected; this is agreeable to the will of God: false balances are abominable to him; such as carnal reason, vain philosophy, and the traditions of men, used by antichrist and his followers; the harlot, described in some preceding chapters, opposed to Wisdom or Christ, who directs to the search of the Scriptures, and the use of them to try doctrines by, John 5:39; see Acts 17:11.
(c) "lapsis perfectus", Montanus, Gejerus. (d) , &c. Phocylid. Poem. Admon. v. 12, 13.

However men may make light of giving short weight or measure, and however common such crimes may be, they are an abomination to the Lord.

(Proverbs. 11:1-31)
(Compare Margin). The Hebrews used stones for weights.
just--complete in measure.

The next three proverbs treat of honesty, discretion, and innocence or dove-like simplicity:
1 Deceitful balances are an abomination to Jahve;
But a full weight is His delight.
The very same proverb, with slightly varied expression, is found in Proverbs 20:23; and other such like proverbs, in condemnation of false and in approbation of true balances, are found, Proverbs 20:10; Proverbs 16:11; similar predicates, but connected with other subjects, are found at Proverbs 12:22; Proverbs 15:8. "An abomination to Jahve" is an expression we have already twice met with in the introduction, Proverbs 3:32; Proverbs 6:16, cf. Proverbs 8:7; תּועבה is, like תּועה, a participial noun, in which the active conception of abhorring is transferred to the action accomplished. רצון is in post-biblical Hebr. the designation of the arbitrium and the voluntas; but here רצונו signifies not that which God wishes, but that which He delights in having. "מרמה (here for the first time in Proverbs), from רמה, the Piel of which means (Proverbs 26:19) aliquem dolo et fraude petere. אבן, like the Pers. sanak, sanakh, Arab. ṣajat, a stone for weight; and finally, without any reference to its root signification, like Zac 5:8, אבן העופרת, a leaden weight, as when we say: a horseshoe of gold, a chess-man of ivory."

A false balance - The use of all false weights and measures in commerce.