'Bowing' in the Bible

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?

The children of your oppressors will come bowing to you; all who treated you with disrespect will bow down at your feet. They will call you, 'The City of the Lord, Zion of the Holy One of Israel.'