What is God's word about raising dogs, such as pit bulls, on chains their whole life and selling them for fighting or fighting them yourself?
In Hebrew society, dogs were a despised animal. They were domesticated for guard duties (Job 30:1). But the problem is that there were no leash laws, dog catchers, or humane societies to deal with stray dogs. Ancient cities often had packs of stray dogs wandering the streets living off the refuge dumps, ready to eat anything they could find that was edible. "And at evening they return, they growl like a dog, and go all around the city. They wander up and down for food, and howl if they are not satisfied" (Psalm 59:14-15). In times of war, they would appear in the aftermath (Psalm 68:23; I Kings 14:11; Jeremiah 15:3).
Thus, people would throw stones or swing sticks at stray dogs to keep them away (I Samuel 17:43). Because you just never knew when a stray dog might turn on you (Matthew 7:6).
But God does teach animals were to be treated with kindness. "A righteous man regards the life of his animal, but the tender mercies of the wicked are cruel" (Proverbs 12:10). This is were people who raise animals for fights demonstrate the corruption of their own souls. There is nothing kind about forcing animals to attack other animals.