It can be stated plainly that it was the army and not the rulers by themselves who attacked Israel. AT: "the Philistine rulers led their army and attacked Israel" (See: [[rc://en/ta/man/translate/figs-explicit]])
The "hand" is a metonym for the power of the person. AT: "save us from the Philistine army" or "keep the Philistine army from harming us" (See: [[rc://en/ta/man/translate/figs-metonymy]])