Compare Proverbs 16:33 note. A tacit appeal to the Divine Judge gave a fairer prospect of a just decision than corruption Proverbs 18:16 or hasty onesidedness Proverbs 18:17.

The lot causeth contentions to cease - See note on Proverbs 16:33.

The lot (l) causeth contentions to cease, and (m) parteth between the mighty.
(l) If a controversy cannot otherwise be decided, it is best to cast lots to know whose the thing will be.
(m) Appeases their controversy, who are so stout that they cannot otherwise be pacified.

The lot causeth contentions to cease,.... When a case cannot be determined among parties at variance in a private way, nor in a court of judicature, the lot is cast, and that puts an end to all strife, and makes each party easy; they submit to it, and acquiesce in it;
and parteth between the mighty; the kings and princes of the earth; men of great power and authority, and of great riches and affluence; and so in a capacity of contending with each other, and of prolonging the contention, which may be attended with bad consequences; and who are not easily dissuaded from it: or it may intend such who most vehemently disagree; persons of great spirits, who are obstinate and stubborn, and will by no means yield, and there is no parting them by arguments or legal decisions; these the lot parts, and causes them to cease from their quarrels and contentions, and to rest satisfied with the distributions the lot makes to them; as the children of Israel were with their portion of the land of Canaan, assigned them by lot.

It was customary sometimes to refer matters to God, by casting lots, with solemn prayer. The profaning the lot, by using it in matters of diversion, or coveting what belongs to others, forms an objection to this now.

The lot--whose disposal is of God (Proverbs 16:13), may, properly used, be a right mode of settling disputes.

18 The lot allayeth contentions,
And separateth between the mighty,
i.e., erects a partition wall between them - those contending (הפריד בּין, as at 2-Kings 2:11, cf. Arab. frḳ byn); עצוּמים are not opponents who maintain their cause with weighty arguments (עצּמות, Isaiah 41:21), qui argumentis pollent (vid., Rashi), for then must the truth appear in the pro et contra; but mighty opponents, who, if the lot did not afford a seasonable means of reconciliation, would make good their demands by blows and by the sword (Fl.). Here it is the lot which, as the judgment of God, brings about peace, instead of the ultima ratio of physical force. The proverb refers to the lot what the Epistle to the Hebrews; Hebrews 6:16, refers to the oath, vid., at Proverbs 16:33. Regarding מדינים and its altered forms, vid., p. 145.

Parteth - Gives to every one what is right or meet.