David speaks as if God were on land above a flood and had physical hands with which he could pull David out of a flood. The flood is a metaphor for the troubles caused by the "foreigners." AT: "You who are able to act, help me overcome my troubles" (See: [[rc://en/ta/man/translate/figs-metaphor]])
Possible meanings are 1) David speaks of the custom of raising the right hand to swear that what one is about to say in court is true, "they lie even when they swear to tell the truth," or 2) the "right hand" is a metaphor for power, "everything they have gotten, they have gotten by telling lies." (See: [[rc://en/ta/man/translate/figs-metaphor]])