Dora Bas Rivka Silver O'H
Remember Psalm 40?
This song is labeled, "to remember," an uncommon introduction that only appears on one other Psalm (#38). The intention appears to be a plea by David that G-d remember him.
David asks G-d to rush to his rescue, since he has been disgraced by his pursuers. He hopes that those who have persecuted him suffer these indignities instead. They deserve this fate for trying to impose it upon David, who is innocent. The enemies laughed and cheered at David's disgrace; David would prefer to see rejoicing from those who seek G-d and who always praise Him. Since David has been made lowly, he prays to G-d to hurry to his aid. G-d is the only One who can help David escape his troubles, so he prays for G-d's imminent arrival.
This Psalm in its entirety is virtually identical to the end of Psalm 40. The Malbim suggests that Psalm 40 was recited, as many Psalms were, while David was fleeing from Saul. This Psalm was recited many years later, as David was on the run from his son Avshalom. If so, the remembering that David asks in the introduction may be David asking G-d to recall how He rescued him then, and to repeat it.