The word "God" is not in the original, and the adjective translated "great" is never used elsewhere absolutely in that sense. The simplest and best interpretation is: As the archer that woundeth everyone, so is he who hireth the fool, and he who hireth every passerby. Acting at random, entrusting matters of grave moment to men of bad repute, is as likely to do mischief as to shoot arrows at everyone.

The great God that formed all things - Or, A great man grieveth all, and he hireth the fool, he hireth also transgressors, where this verse is very differently translated. I shall add that of Coverdale: "A man of experience discerneth all thinges well: but whoso hyreth a foole, hyreth soch one as wyl take no hede." The רב rab may mean either the great God, or a great man: hence the two renderings, in the text and in the margin.

(f) The great [God] that formed all [things] both rewardeth the fool, and rewardeth transgressors.
(f) Meaning God.

The great God, that formed all things,.... That made the heavens, earth, and sea, and all that are in them; who is great in the perfections of his nature, and in the works of his hands, and greatly to be praised;
both rewardeth the fool, and rewardeth transgressors; according to their works; every transgression of the law receiving its just recompence of reward, whether a man transgresses it ignorantly or wilfully; as his transgressions are, whether through error or presumption, so shall his punishment be; though some understand this, as Kimchi, of the Lord's doing good in a providential way, to the wise and unwise, the righteous and the wicked: the words are by some rendered to another sense, "a great one grieveth all, and he hireth the fool, and he hireth the transgressors" (y); that is, a great man, a tyrannical prince, grieves all his good subjects; or, as Hottinger (z), from the use of the word in the Arabic tongue, changes all things, inverts their order, or administers all at his will, that is, wrongly; when he hires fools and wicked men to do those bad things for him which others would not, to the great detriment of the commonwealth; and rewards them for it, putting them into posts of honour and trust, to the great grief and trouble of all his best subjects.
(y) So Mercerus, Piscator. (z) Smegm. Oriental. l. 1. c. 2. p. 171.

This verse may either declare how the Lord, the Creator of all men, will deal with sinners according to their guilt, or, how the powerful among men should disgrace and punish the wicked.

Various versions of this are proposed (compare Margin). Better perhaps--"Much He injures (or literally, "wounds") all who reward," &c., that is, society is injured by encouraging evil men.
transgressors--may be rendered "vagrants." The word "God" is improperly supplied.

All that we have hitherto read is surpassed in obscurity by this proverb, which is here connected because of the resemblance of ושכר to שכור. We translate it thus, vocalizing differently only one word:
Much bringeth forth from itself all;
But the reward and the hirer of the fool pass away.
The lxx translates πολλὰ χειμάζεται πᾶσα σὰρξ ἀφρόνων (all the flesh of fools suffers much), συντριβήσεται γὰρ ἧ ἔκστασις αὐτῶν, which is in Hebrew:
רב מחולל כל בּשׂר כסיל
ישּׁבר עברתם
An unfortunate attempt so to rectify the words that some meaning might be extracted from them. The first line of this translation has been adopted by the Syr. and Targ., omitting only the כל, in which the self-condemnation of this deciphering lies (for כל בשׂר means elsewhere, humanity, not the whole body of each individual); but they translate the second line as if the words were:
ישׁכּר עבר ים
i.e., and the drunken man sails over the sea (עברים is separated into עבר ים, as בבקרים, Amos 6:12, is to be separated into בּבּקר ים); but what does that mean? Does it mean that to a drunkard (but שׁכּור, the drunken man, and not סבא, the drunkard, is used) nothing remains but to wander over the sea? or that the drunken man lets his imagination wander away over the sea, while he neglects the obligation that lies upon him? Symmachus and Theodotion, with the Midrash (Rashi) and Saadia (Kimchi), take שׂכר in 10b = סגר (like Isaiah 19:10, שׂכר = embankment, cf. סכּרין, Kelim, Proverbs 23:5); the former translates by καὶ ὁ φράσσων ἄφρονα ἐμφράσσει τὰς ὀργὰς αὐτοῦ, the latter by καὶ φιμῶν ἄφρονα φιμοῖ χόλους, yielding to the imagination that עברים, like עברות, may be the plur. of עברה, anger. Jerome punctuates רב as, Proverbs 25:8, רב, and interprets, as Symmachus and Theodotion, שׂכר both times = סגר, translating: Judicium determinat causas, et qui imponit stulto silentium iras mitigat; but רב does not mean judicium, nor מחולל determinat, nor כל causas. As Gussetius, so also Ralbag (in the first of his three explanations), Meri, Elia Wilna interpret the proverb as a declaration regarding quarrelsome persons: he causeth woe to all, and hireth fools, hireth transgressors, for his companions; but in that case we must read רב for רב; מחולל, bringing woe, would be either the Po. of חלל, to bore through, or Pilel of חיל (חוּל), to put into distress (as with pangs); but עברים, transgressors = sinners, is contrary to the O.T. usus loq., Proverbs 22:3 (Proverbs 27:12) is falsely cited in its favour; besides, for רב there should have been at least אישׁ רב and why שׂכרו is repeated remains inexplicable. Others take מחולל־כל as the name of God, the creator of all men and things; and truly this is the nearest impression of these two words, for חולל is the usual designation for divine production, e.g., Psalm 90:2. Accordingly Kimchi explains: The Lord is the creator of all, and He gives to fools and to transgressors their maintenance; but עברים, transgressors, is Mishnic, not bibl.; and שׂכר means to hire, but not to supply with food. The proverb is thus incapable of presenting a thought like Matthew 5:45 (He maketh His sun to rise on the evil and on the good). Others translate: "The Lord is creator of all, and takes fools, takes idlers, into His service." Thus rendered, the proverb is offensive; wherefore Rashi, Moses Kimchi, Arama, and others regard the Mashal as in the mouth of fools, and thus they take Proverbs 26:9 and Proverbs 26:10 together as a tetrastich. Certainly this second collection of proverbs contains also tetrastiches; but Proverbs 26:9 and Proverbs 26:10 cannot be regarded as together forming a tetrastich, because רב (which is valid against Kimchi also) cannot mean God the Lord: רב, Lord, is unheard of in bibl. Hebrews., and at least the word הרב must be used for God. The Venet. on this account does not follow Kimchi, but translates, Ἄρχων πλάττει πάντα, καὶ μισθοῦται μωρὸν καὶ μισθοῦται ὡς παραβάτης (ought to have been παραβάτας); but who could this cunning man be? Perhaps the Venet. is to be understood, after Gecatilia (in Rashi): a great (rich) man performs all manner of things; but if he hires a fool, it is as if he hired the first best who pass along the way. But that חולל is used in the general sense of to execute, to perform, is without example, and improbable. Also the explanation: a ruler brings grief, i.e., severe oppression, upon all (Abulwald, Immanuel, Aben Ezra, who, in his smaller grammar, explains רב = רב after Isaiah 49:9; C. B. Michaelis: dolore afficit omnes), does not recommend itself; for חולל, whether it be from חלל, Isaiah 51:9 (to bore through), or from חיל, Psalm 29:9 (to bring on the pangs of birth), is too strong a word for hurting; also the clause, thus generally understood, is fortunately untrue. Translated as by Euchel: "the prominent persons destroy all; they keep fools in pay, and favour vagabonds," - it sounds as if it had been picked up in an assembly of democrats. On the other hand, the proverb, as translated by Luther:
A good master maketh a thing right;
But he who hireth a bungler, by him it is spoiled,
is worthy of the Book of Proverbs. The second line is here freely rendered, but it is also appropriate, if we abide closer by the words of the text, in this connection. Fleischer: Magister (artifex peritus) effingit omnia (i.e., bene perficit quaecunque ei committuntur); qui autem stultum conducit, conducit transeuntes (i.e., idem facit ac si homines ignotos et forte transeuntes ad opus gravius et difficilius conduceret). Thus also Gesenius, Bttcher, and others, who all, as Gecatilia above, explain עברים, τοὺς τυχόντας, the first best. But we are reluctantly constrained to object to this thought, because רב nowhere in bibl. Hebrew signifies a master; and the ו of the second ושׂכר dno cannot bear that rendering, ac si. And if we leave it out, we nevertheless encounter a difficulty in חולל, which cannot be used of human production. Many Christian interpreters (Cocceius, Schultens, Schelling, Ewald, Bertheau, Stier, Zckler) give to רב a meaning which is found in no Jewish interpreter, viz., sagittarius, from רבב (רבב), Genesis 49:23 (and perhaps Psalm 18:15), after the forms צר, שׂר, the plur. of which, רבּים, is found at Job 16:13; Jeremiah 50:29, but in a connection which removes all doubt from the meaning of the word. Here also רב may be more closely defined by מחולל; but how then does the proverb stand? "an archer who wounds everything, and he who hires a fool, and hires passers-by" (Ewald: street-runners), i.e., they are alike. But if the archer piercing everything is a comic Hercules furens, then, in order to discover the resemblance between the three, there is need of a portion of ingenuity, such as is only particularly assigned to the favoured. But it is also against the form and the usage of the word to interpret עברים simply of rogues and vagabonds. Several interpreters have supposed that רב and כל must stand in a certain interchangeable relation to each other. Thus, e.g., Ahron b. Josef: "Much makes amazement to all, but especially one who hires a fool...." But this "especially" (Before all) is an expression smuggled in. Agreeing with Umbreit and Hitzig, we translate line first; but in translating line second, we follow our own method:
Much bringeth all out of it;
i.e., where there is much, then one has it in his power, if he begins right, to undertake everything. רב has by כּל the definition of a neuter, so as to designate not only many men, Exodus 19:21, but also much ability in a pecuniary and facultative sense (cf. the subst. רב, Isaiah 63:7; Psalm 145:7); and of the much which bringeth forth all out of itself, effects all by itself, חולל with equal right might be used, as Proverbs 25:23, of the north wind. The antithesis 10b takes this form:
But the reward (read וּשׂכר) and the master (who hires him for wages) of the fool pass away,
i.e., perish; עברים, as if עבר, is used of chaff, Isaiah 29:5; of stubble, Jeremiah 13:24; of shadow, Psalm 144:4. That which the fool gains passes away, for he squanders it; and he who took him into his service for wages is ruined along with him, for his work is only pernicious, not useful. Although he who possesses much, and has great ability, may be able to effect everything of himself, yet that is not the case when he makes use of the assistance therein of foolish men, who not only do not accomplish anything, but, on the contrary, destroy everything, and are only ruinous to him who, with good intention, associates them with himself in his work. That the word must be more accurately ושׂכר, instead of ושׂכרוו, one may not object, since ושׂכר is perfectly unambiguous, and is manifestly the object.

Rewardeth - Will certainly give that recompence which is deserved by fools and transgressors, by such as sin either thro' ignorance, or wilfully.