Samuel's era of leadership ushered in a profound period of physical security and spiritual renewal for the Israelites, granting them a rare time of absolute peace from their surrounding enemies. Following a crushing defeat, the Philistine threat was broken. They surrendered and entirely stopped launching large, organized military raids across the Israelite borders [רלב״ג, ביאור שטיינזלץ].
This military advantage extended far beyond mere border defense. Whenever the Israelites took the initiative to launch offensive campaigns deep inside Philistine territory, God stood by their side. His providence actively struck the enemy on their own soil, ensuring victory even outside the borders of Israel [מלבי״ם, מצודת דוד].
This remarkable period of safety and Divine favor, however, did not last for Samuel's entire life. It remained intact only during his active years of leadership. As Samuel grew older, he was no longer able to travel from city to city to guide the nation and correct their behavior. Without his constant, active presence, the Israelites experienced a sharp spiritual decline. Because of these sins, the Philistines eventually returned to oppress the nation during Samuel's final years. It was this renewed state of distress and vulnerability that ultimately drove the people to demand a human king to lead and protect them [רד״ק, מלבי״ם, מצודת דוד].