Whose mouth speaketh vanity, and their right hand is a right hand {g} of falsehood.

(g) For though they shake hands, they do not keep their promises.

Wesley's Notes

144:8 Vanity - Vain brags and threatenings which shall come to nothing. Falsehood - Deceiving themselves, by being unable to do what they designed; and others, by not giving them that help which they promised.

Matthew Henry's Concise Commentary

144:1-8 When men become eminent for things as to which they have had few advantages, they should be more deeply sensible that God has been their Teacher. Happy those to whom the Lord gives that noblest victory, conquest and dominion over their own spirits. A prayer for further mercy is fitly begun with a thanksgiving for former mercy. There was a special power of God, inclining the people of Israel to be subject to David; it was typical of the bringing souls into subjection to the Lord Jesus. Man's days have little substance, considering how many thoughts and cares of a never-dying soul are employed about a poor dying body. Man's life is as a shadow that passes away. In their highest earthly exaltation, believers will recollect how mean, sinful, and vile they are in themselves; thus they will be preserved from self-importance and presumption. God's time to help his people is, when they are sinking, and all other helps fail.