# empowered him

This means that Yahweh helped Othniel to develop the qualities he needed to be a great leader.

# he judged Israel

Here "judged" means he led the people of Israel.

# he went out to war

"Othniel and the Israelite soldiers went to fight against the army of Cushan-Rishathaim" 

# Yahweh gave him victory over Cushan-Rishathaim king of Aram

"Yahweh helped the Israelite army defeat the army of Cushan-Rishathaim king of Aram”