Those who were called from Naphtali, Asher, and Manasseh were quite likely the soldiers he had earlier sent home. He also summoned volunteers from Ephraim to capture the waters over the Jordan in order to cut off any retreat for the remnant of Midian. Some, like Assis, believe this to be acceptable, as part of the mopping-up operation:
The first stage was the battle and the second stage is the pursuit. The first stage determined the victor, and in the second stage, in the pursuit, the victorious side wishes to destroy the vanquished side and thereby to determine a clear victory…. In the first stage of the war, Gideon was constrained to have a small army because of God’s concern that otherwise the Israelites would attribute the victory to themselves and not to divine assistance. Thus, only three hundred soldiers participated in the actual battle, and at this stage the miracle of the victory of the few over the mighty and well equipped Midianite army was clearly seen. Now, already there is no reason for additional soldiers not to come to Gideon’s aid for the pursuit stage, in which Israel will endeavour to eliminate the Midianite threat.1
Others object to Gideon’s decision here. Having achieved the divinely intended goal with the three hundred core troops, Gideon appeared to forget the point of Yahweh’s reduction of the troops. Instead of operating by faith and seeking guidance from God, he relied on human strength.
2
The latter seems more likely. Gideon’s call is sign of his growing self-confidence.
23 And the men of Israel were called out from Naphtali and from Asher and from all Manasseh, and they pursued after Midian.