A Commentary, Critical, Practical, and Explanatory on the Old and New Testaments, by Robert Jamieson, A.R. Fausset and David Brown  at sacred-texts.com
psa 58:1David's critical condition in some period of the Sauline persecution probably occasioned this Psalm, in which the Psalmist teaches that the innate and actual sinfulness of men deserves, and shall receive, God's righteous vengeance, while the pious may be consoled by the evidence of His wise and holy government of men. (Psa 58:1-11)
O congregation--literally, "Oh, dumb"; the word used is never translated "congregation." "Are ye dumb? ye should speak righteousness," may be the translation. In any case, the writer remonstrates with them, perhaps a council, who were assembled to try his cause, and bound to give a right decision.
psa 58:2This they did not design; but
weigh . . . violence--or give decisions of violence. Weigh is a figure to express the acts of judges.
in the earth--publicly.
psa 58:3describe the wicked generally, who sin naturally, easily, malignantly, and stubbornly.
psa 58:4stoppeth her--literally, "his."
ear--that is, the wicked man (the singular used collectively), who thus becomes like the deaf adder which has no ear.
psa 58:6He prays for their destruction, under the figure of ravenous beasts (Psa 3:7; Psa 7:2).
psa 58:7which run continually--literally, "they shall go to themselves," utterly depart, as rapid mountain torrents.
he bendeth . . . his arrows--prepares it. The term for preparing a bow applied to arrows (Psa 64:3).
let them . . . pieces--literally, "as if they cut themselves off"--that is, become blunted and of no avail.
psa 58:8Other figures of this utter ruin; the last denoting rapidity. In a shorter time than pots feel the heat of thorns on fire--
psa 58:9he shall take them away as with a whirlwind--literally, "blow him (them) away."
both living . . . wrath--literally, "as the living" or fresh as the heated or burning--that is, thorns--all easily blown away, so easily and quickly the wicked. The figure of the "snail" perhaps alludes to its loss of saliva when moving. Though obscure in its clauses, the general sense of the passage is clear.
psa 58:10wash . . . wicked--denoting great slaughter. The joy of triumph over the destruction of the wicked is because they are God's enemies, and their overthrow shows that He reigneth (compare Psa 52:5-7; Psa 54:7). In this assurance let heaven and earth rejoice (Psa 96:10; Psa 97:1, &c.).