Albert Barnes Commentary 2 Samuel 3:8

"Then was Abner very wroth for the words of Ish-bosheth, and said, Am I a dog`s head that belongeth to Judah? This day do I show kindness unto the house of Saul thy father, to his brethren, and to his friends, and have not delivered thee into the hand of David; and yet thou chargest me this day with a fault concerning this woman." — 2 Samuel 3:8 (ASV)

The words against Judah are very obscure. If the text is correct, the words would seem to be Ish-bosheth’s, who in his anger had charged Abner with being a vile partisan of Judah. Abner retorts, “Am I (as you say) a dog’s head which belongs to Judah, or on Judah’s side! This day I show you kindness, etc., and this day you charge me with a fault, etc.”