C.H. Spurgeons's The Treasury of David
Verse 8. Whose mouth speaketh vanity. No wonder that men who are vanity speak vanity. "When he speaketh a lie, he speaketh of his own. "They cannot be depended upon, let them promise as fairly as they may: their solemn declarations are light as the foam of the sea, in no wise to be depended upon. Good men desire to be rid of such characters: of all men deceivers and liars are among the most disgusting to true hearts.
And their right hand is a right hand of falsehood. So far their hands and their tongues agree, for they are vanity and falsehood. These men act as falsely as they speak, and prove themselves to be all of a piece. Their falsehood is right handed, they lie with dexterity, they deceive with all their might. It is a dreadful thing when a man's expertness lies more in lies than in truth; when he can neither speak nor act without proving himself to be false. God save us from lying mouths, and hands of falsehood.
EXPLANATORY NOTES AND QUAINT SAYINGS
Verse 8. Whose mouth speaketh vanity, etc. Two things go naturally together in the verse - - the lying tongue and deceitful hand. The meaning is that upon the matter in hand nothing was to be looked for from any of their promises, since it was only to deceive that they flattered with their mouth and gave the hand. --John Calvin.
Verse 8. Their right hand is a right hand of falsehood. The pledge of the right hand, which used to be a witness of good faith, was violated by treachery and wickedness. -- Cicero. Philip. xi. c. 2.
HINTS FOR PASTORS AND LAYPERSONS
Verse 8. What is "a right hand of falsehood"? Ask the hypocrite, the schemer, the man of false doctrine, the boaster, the slanderer, the man who forgets his promise, the apostate.