They were grinding barley forcefully until the man pay the debt to the person.
The man's wife and daughter were forced to grind barley until the man paid his debt because the person wanted to recover his money from the man by forcing him. The person takes the advantage of work from the wife and daughter by doing household work from them such as grinding of barley etc. This act of person will compel the man to collect money from anywhere in order to buy the freedom of his wife and daughter but until his wife and daughter will do the work at the person's house from which the man takes money.
