Charles Ellicott Commentary Psalms 140:2

"Who devise mischiefs in their heart; Continually do they gather themselves together for war." — Psalms 140:2 (ASV)

Imagine ...—Or, contrive, plot.

Gathered together.— This translation follows the analogy of Psalms 56:6. Others render it, “dwell with wars.” But it is preferable to derive it from a root meaning to incite: “They are continually stirring up wars.” This is the situation described in Psalms 120:7 and frequently elsewhere: Israel would be at peace, but within and without are those always trying to involve her in troubles.