Judges 15:20

And he judged Israel in the days of the Philistines twenty years. While they had the power over the Israelites, who were not entirely delivered out of their hands by Samson, he only began to deliver them, but did not completely do it; though he got many advantages over them, and wrought many salvations and deliverances, yet was not the author of perfect salvation, see Judges 13:5 however, he was a check upon the Philistines, and protected the Israelites from heavier oppressions, which otherwise they would have come under; and no doubt administered justice and judgment among them, and was an instrument of their reformation, and of preserving them from idolatry; for in such things the work of a judge chiefly lay: some from hence observe, that this shows the years of servitude and bondage are included in the years of the judges.