2 Samuel 3:8

Am I a dog's head, &c. Render, Am I a dog's head belonging to Judah? This day do I shew kindness … and thou hast charged me! &c. i.e. Am I at once despicable and hostile to your interests? Nay, I am faithful to the house of Saul, otherwise I should long ago have made terms with David by surrendering you into his hands.

In the East in ancient times as at the present day, dogs, although used for guarding flocks and houses (Job 30:1; Isaiah 56:10), were chiefly seen prowling about towns in a half-wild condition, owning no master, living on offal and garbage. Cp. Psalms 59:14-15; 1 Kings 21:19; 1 Kings 21:23-24; 1 Kings 22:38. Hence the aversion with which they were regarded, and "dog" became (1), as here, a term of reproach and contempt; cp. 1 Samuel 17:43; 1 Samuel 24:14; 2Sa 9:8; 2 Samuel 16:9; 2 Kings 8:13: (2) an expression for fierce and cruel men (Psalms 22:16): (3) a name for impure persons (Matthew 7:6; Philippians 3:2; Revelation 22:15). See Tristram's Nat. Hist. of the Bible, p. 78.