Its to humble our souls
Psalm 69:10
When I wept and humbled my soul with fasting, it became my reproach.
Isaiah 58:5-6
"Is it a fast like this which I choose, a day for a man to humble himself? Is it for bowing one's head like a reed And for spreading out sackcloth and ashes as a bed? Will you call this a fast, even an acceptable day to the LORD? 6"Is this not the fast which I choose, To loosen the bonds of wickedness, To undo the bands of the yoke, And to let the oppressed go free And break every yoke?...
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Its also a Telegram to put things before the Lords throne
Ezra 8:23
So we fasted and implored our God for this, and he listened to our entreaty.
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Disciplining your body
1 Corinthians 9:27
But I discipline my body and keep it under control, lest after preaching to others I myself should be disqualified.
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And for spiritual deliverance...
Mark 9:29
And he said unto them, This kind can come forth by nothing, but by prayer and fasting.
And Jesus said when you fast..not if you fast
Matthew 6:16
“And when you fast, do not look gloomy like the hypocrites, for they disfigure their faces that their fasting may be seen by others. Truly, I say to you, they have received their reward.