'Fast' in the Bible

'Why have we fasted, and Thou hast not seen? We have afflicted our soul, and Thou knowest not.' Lo, in the day of your fast ye find pleasure, And all your labours ye exact.

Lo, for strife and debate ye fast, And to smite with the fist of wickedness, Ye fast not as to -day, To sound in the high place your voice.

Like this is the fast that I choose? The day of a man's afflicting his soul? To bow as a reed his head, And sackcloth and ashes spread out? This dost thou call a fast, And a desirable day -- to Jehovah?

Is not this the fast that I chose -- To loose the bands of wickedness, To shake off the burdens of the yoke, And to send out the oppressed free, And every yoke ye draw off?