Final answer:
Saul was replaced by David, who did not usurp the throne. David became the second king of Israel and was able to drive back the Philistines.
Step-by-step explanation:
Saul was replaced as king by David, who did not usurp the throne from him. David was one of Saul's former lieutenants. After Saul's rule, David became the second king of Israel. He not only ruled effectively but also was able to drive back the Philistines, who were oppressing the Hebrews. David's son Solomon succeeded him as king.