God does not want a person to be held in a place by a contract or covenant if they will be treated violently. The Law of Moses allows a man who has fallen into debt to bond himself to work as a servant for a person who would pay off his debts in return.
If a man strikes the eye of his male or female servant, and destroys it, he shall let him go free for the sake of his eye. And if he knocks out the tooth of his male or female servant, he shall let him go free for the sake of his tooth (Ex 21:26-27).This command applies to both men and women. A wife has greater freedom than a female bondservant. So if violence sets a servant free, violence must set a wife free too.
Violence nullifies a covenant or contract. When a man is violent towards his wife, his treachery to the marriage covenant annuls it.