Thou hast trodden down all them that err from thy statutes - Compare the notes at Psalms 119:21. Rather, “Thou hast made light of,” or “thou despisest.” The Hebrew word means properly to suspend in a balance; to weigh. Then it means to lift up lightly or easily; and then, to make light of; to contemn; to regard anything as “light.” The Septuagint and Latin Vulgate render it, “Thou dost despise.” That is, God regards them as of no account; as a light substance of no value; as chaff which the wind carries away. Compare Job 21:18; Psalms 1:4; Psalms 35:5; Isaiah 17:13.
For their deceit is falsehood - This seems to be a truism - for deceit must imply falsehood. In the original this is an emphatic way of declaring the whole thing to be false, as the Hebrew language often expresses emphasis by mere repetition - thus “pits, pits,” meaning many pits. The psalmist first characterizes their conduct as deceitful - as that which cannot be relied on - as that which must fail in the end; he then speaks of this system on which they acted as altogether a “lie” - as that which is utterly “false;” thus giving, as it were, a double emphasis to the statement, and showing how utterly delusive and vain it must be.