When the Israelites cried out to the Lord [for help], the Lord raised up a [p]man to rescue the people of Israel, [q]Othniel the son of Kenaz, Caleb’s younger brother. The Spirit of the Lord came upon him, and he judged Israel. He went out to war, and the Lord gave Cushan-rishathaim king of Mesopotamia into his hand, and he prevailed over Cushan-rishathaim. And the land was at rest [from oppression for] forty years. – Judges 3:9-11
Soon after Israel’s settlement in Canaan their purity began to be corrupted, and their peace disturbed. But affliction makes those cry to God who before would scarcely speak to him. God returned in mercy to them for their deliverance. The Spirit of the Lord came upon Othniel. The Spirit of wisdom and courage to qualify him for the service, and the Spirit of power to excite him to it. He first judged Israel, reproved and reformed them, and then went to war. Let sin at home be conquered, that worst of enemies, then enemies abroad will be more easily dealt with. Thus let Christ be our Judge and Lawgiver, then he will save us. – Matthew Henry Commentary
Gary Inrig explains that…
The Lord uses those difficulties to teach us how to wage spiritual war. He wants to shake us out of our apathy and teach us to trust Him. Often it is only when the enemy has run all over us, and our resources are gone, that we develop a teachable spirit. There are times in our lives when the roof gets blown off, and everything seems to fall to pieces. Those times of failure and crisis become teaching times as the Lord shows us how to make war—how to trust Him.
In the Old Testament, the Spirit was not yet the permanently indwelling Spirit we find in the New Testament; instead, He temporarily “came on” people to help them fill a particular role or purpose. In most of these cases, the empowerment came so God might use His leader for the sake of the many. The “judges” were deliverers, impelled and empowered by the Spirit of God. These individuals gained justice for the Israelites by defeating their enemies, who were oppressing them.