Being called a dog was a major insult in Biblical times
Proverbs 26:11
Like a dog that returns to its vomit, So is a fool who repeats his foolishness.
Deuteronomy 23:18
You shall not bring the earnings of a prostitute or the money for a dog into the house of the Lord your God as payment for any vowed offering, because both of these are an abomination to the Lord your God.
Judges 7:5
So he brought the people down to the water. Then the Lord said to Gideon, “You shall put everyone who laps the water with his tongue as a dog laps in one group, and everyone who kneels down to drink in another.”
2 Samuel 3:8
Then Abner became very angry over Ish-bosheth’s question and said, “Am I a dog’s head that belongs to Judah? Today I show kindness to the house of Saul your father, to his brothers and to his friends, and have not let you fall into the hands of David; yet today you call me to account for wrongdoing with that woman?
Psalm 22:16
For dogs have surrounded me; A band of evildoers has encompassed me; They pierced my hands and my feet.
Beats me