true fasting

Isaiah 58

humble

‘Why have we fasted,’ they say, ‘and you have not seen it? Why have we humbled ourselves, and you have not noticed?’ “Yet on the day of your fasting, you do as you please and exploit all your workers.
Isaiah 58:3 NIV
http://bible.com/111/isa.58.3.NIV

pray and fasting change God mind.

When God saw what they did and how they turned from their evil ways, he relented and did not bring on them the destruction he had threatened.
Jonah 3:10 NIV
http://bible.com/111/jon.3.10.NIV

what Jonah did? even animals also fast.

This is the proclamation he issued in Nineveh: “By the decree of the king and his nobles: Do not let people or animals, herds or flocks, taste anything; do not let them eat or drink.
Jonah 3:7 NIV
http://bible.com/111/jon.3.7.NIV