While on the surface it may not seem of much significance, it is very significant, especially when it is noted that the mention of the death of a leader resounds throughout the book. We see it earlier in Judges 1:1 and Judges 2:8 concerning Joshua, and in Judges 2:10 concerning his generation. Now it concerns the first deliverer. The notice is a continual reminder that there is no lasting deliverer for Israel. For unfortunately, the other eleven of the twelve deliverers will not continue Othniel’s pattern…. That should signal to us that the book of Judges is not about the judges of Israel, but about the grace of God.
1 Othniel was in many respects the perfect judge: "he had a perfect lineage, a perfect name, and the perfect enemy. But he died. That was the problem with all the judges. They all died and Israel had no one to rule over them. None of the judges was 'perfect' in any sense. None brought lasting peace; none completely unified Israel against her common foe.”2
11 So the land had rest forty years. Then Othniel the son of Kenaz died.