From BiblePortal Wikipedia

Dogs [1]

Were held in great contempt by the Jews, but were worshipped, as well as cats, by the Egyptians. Among the Jews, to compare a person to a dog was the most degrading expression possible,  1 Samuel 17:43   24:14   2 Samuel 9:8 . The state of dogs among the Jews was the same that now prevails in the East, where, having no owners, they run about the streets in troops, and are fed by charity or caprice, or live on such offal as they can pick up. As they are often on the point of starvation, they devour corpses, and in the night even attack living men,  Psalm 59:6,14,15   1 Kings 14:11 . In various places in Scripture the epithet "dogs" is given to certain classes of men, as expressing their insolent rapacity,  Matthew 7:6   Psalm 22:16   Philippians 3:2 , and their beastly vices,  Deuteronomy 23:18   2 Peter 2:22   Revelation 22:15 .