The Spirit of Yahweh came on him, and he judged Israel; and he went out to war, and Yahweh delivered Cushan Rishathaim king of Mesopotamia into his hand: and his hand prevailed against Cushan Rishathaim.
Contrast the character of Samson, the last judge in the book. The most important factor in the story of Othniel, I believe, was the fact that God’s Spirit empowered him (Judges 3:10). This was true of all the judges, though the writer did not always mention it. No one can accomplish anything significant spiritually without the Holy Spirit’s enablement (cf. Zechariah 4:6; John 15:5). However, with His assistance, His people can be the agents of supernatural change and can carry out God’s will.