'Fasting' in the Bible

Look, your fasting is accompanied by arguments, brawls, and fistfights. Do not fast as you do today, trying to make your voice heard in heaven.

Is this really the kind of fasting I want? Do I want a day when people merely humble themselves, bowing their heads like a reed and stretching out on sackcloth and ashes? Is this really what you call a fast, a day that is pleasing to the Lord?