John Gill Commentary Psalms 58:10

"The righteous shall rejoice when he seeth the vengeance: He shall wash his feet in the blood of the wicked;" — Psalms 58:10 (ASV)

The righteous shall rejoice when he seeth the vengeance
Before imprecated and foretold; the punishment inflicted by the Lord, to whom vengeance belongs, in a way of vindictive wrath; for what befalls the wicked in an afflictive way is in wrath, and as a vengeance upon them: and as the judgments of God are sometimes manifest, are to be seen, they are observed by the righteous, who rejoice at them; not as evils and miseries simply considered, nor from a private affection; but as the glory of divine justice is displayed therein, and the goodness of God is shown to them, by delivering them out of their hands;

See (Revelation 18:20) (19:1-3) ;

he shall wash his feet in the blood of the wicked ;
which denotes the great destruction of the wicked, and the abundance of blood that shall be shed; see (Revelation 14:20) ; and the entire victory the saints shall have over them, and their security from them, (Psalms 68:21–23) ; as well as the satisfaction, and pleasure and refreshment, as it were, they shall have in their destruction; signified by their feet being washed in their blood, instead of being washed in water, usual in the eastern countries; because of the glory of the divine perfections appearing therein.

The Septuagint, Vulgate Latin, and all the Oriental versions, read, "his hands".