Here "Pay back to them" represents punishing them. What they have done can be stated clearly. Alternate translation: "Punish them as they deserve, Yahweh, according to what they have done" or "Yahweh, they have made me suffer, so please make them suffer just as much" (See: [[rc://en/ta/man/jit/figs-metaphor]] and [[rc://en/ta/man/jit/figs-explicit]])