2 Samuel 3:8

Then was Abner very wroth for the words of Ishbosheth, and said, [Am] I a dog's head, which against Judah do shew kindness this day unto the house of Saul thy father, to his brethren, and to his friends, and have not delivered thee into the hand of David, that thou chargest me to day with a fault concerning this woman?

Ver. 8. Am I a dog's head?] An persona canina sum? Am I so worthless and abject? as some sense it; what! a dog, or a dog-keeper? Others, Am I so given to lust and lasciviousness, as dogs are? Thus Deuteronomy 23:18, the price of a bitch, that is, of a whore, which, as a suit-bitch, is followed up and down by her libidinous lecherous paramours. Aristogiton, an Athenian orator, was for this cause called Dog: and it was not permitted to a dog to enter into the Acropolis or tower at Athens, for his heat in venery, and for his ill favour. Goats likewise came not there, saith Varro, unless for necessary sacrifice. a

a Plutarch.