15 And the princes of Issachar were with Deborah; even Issachar, and also Barak: he was sent on foot into the valley. For the divisions of Reuben there were great thoughts of heart.
(Judges 5:15) The leaders of Issachar were with Deborah. In Hebrew: the princes, that is, the teachers of the Law, were with Deborah to praise the Lord, and Barak followed in the footsteps of the age. It is to be understood that a certain part of them remained with Deborah to praise the Lord, and a part followed Barak to exhort and vanquish Sisera. Who, as if into a precipice, gave himself to danger. Barak, indeed, believing the words of the Lord, gave himself to danger, throwing himself into the torrent Kishon, pursuing and vanquishing the army of Sisera. For in this place a raging torrent is understood as the abyss. Ruben, on the other hand, is divided within himself, and a dispute of noble men is found. It is written in the Book of Judges against itself. For the voice of Deborah is heard, rebuking the tribe of Ephraim, because they did not obey the command of the Lord and did not go with their brothers to fight against the enemies of the Lord. But he, being terrified by fear and unbelieving in the words of the Lord, separated himself from them and, because of that, was found to be proud, that is, arrogant. And so their reproof follows in the spirit of prophecy, saying:
Divided against himself: By this it seems that the valient men of the tribe of Ruben were divided in their sentiments, with relation to this war; which division kept them at home within their own borders, to hear the bleating of their flocks.
[AD 420] Jerome on Judges 5:15