God. ha-'Elohim here (= the God), because in connection with Midianites, His creatures. Not Jehovah, App-4.
Related Commentaries of Judges 7:14
Judges 7:14
14 And his fellow answered and said, This is nothing else save the sword of Gideon the son of Joash, a man of Israel: for into his hand hath God delivered Midian, and all the host.