Augustine of Hippo

Dogs should not always be taken in an evil sense; otherwise the prophet would not blame "dogs not able to bark and loving to dream." Doubtless they would be praiseworthy dogs if they both knew how to bark and loved to watch. And certainly those three hundred men—a most sacred number according to the letter of the cross10—would not have been chosen to win the victory because they lapped water as dogs do, unless some great mystery were signified. …

Letter 149 ↗

Gregory the Dialogist

And they are brought to the river, to drink the waters; and whoever drank the waters with bended knees, were removed from the struggle of war. For by the waters is designated the doctrine of wisdom, but by the unbended knee righteous conduct. They therefore who are reported to have bent their knees, while drinking the water, retired from the strife of battles, having been forbidden; because Christ proceeds to battle against the enemies of the faith, with those who when they drink the streams of doctrine, distort not the uprightness …

Morals on the Book of Job, Book 30.74 ↗

Bonaventure

This was marked in the case of Gedeon where those who were tested by the water, that is, those who lapped it like dogs, fought the battle and won, while those who bent their knee to drink were turned away. And those who had won the test were given trumpets and pitchers and lanterns, and they obtained the victory by means of blaring horns and clanging vessels. These are the preachers of the Church who in their preaching make a blaring of horns. The vessels are the bodies, the lanterns are the miracles. …

Collations on the Hexaemeron, Collation 19 ↗