Psalms 68:23

That your foot may be dipped in blood. Because his own foot was dipped in his own blood. "I have trodden the winepress alone, and of the nations there was no man with me." And again: "Who is this who ascends from Edom? his garments red from Bosor." Edom is interpreted "blood," Bosor "flesh": it signifies our Lord himself crucified. The tongue of your dogs from the enemies, from him. By "dogs" he means the Jews themselves, who cried out: "Crucify, crucify such a one: we have no king but Caesar." And "from the enemies": prompted by the demons to deny the Savior, and to blaspheme him. Otherwise: because you yourself came of your own will and suffered, and of your own will you were crucified by the Jews.

But on the other hand, dogs licked the wounds of the poor man lying there. Sometimes in sacred speech preachers are understood by dogs. For the tongue of a dog, when it licks a wound, heals it, because holy teachers too, when they instruct us in the confession of our sin, touch as it were the wound of the mind through their tongue; and because by speaking they rescue us from sins, by touching wounds as it were they restore us to health. For that by the name of dogs the tongue of preachers is signified, the Lord says through the Psalmist: "The tongue of your dogs from enemies, from him." For from the unbelieving Jews the holy preachers were chosen, who, coming against thieves and robbers in defense of the truth, gave great barkings, so to speak, for the Lord.

Likewise, in the same psalm, where it says, "the tongue of your dogs from the enemies by the same," 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": 18 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 cross20—would not have been chosen to win the victory because they lapped water as dogs do, unless some great mystery were signified. Good dogs watch and bark to protect their house and their master, their flock and their shepherd. Finally, even here in the praises offered by the church, when a selection is made from this prophecy, it is the tongue of dogs that is mentioned, not their teeth. "The tongue of your dogs," it says, "from the enemies," that is, that those who used to be your enemies and raged against you may become your dogs and may bark for you. It added "from the same" to make them understand that this is not effected by themselves, but "by the same," that is, by his mercy and grace.