Fasting is used to get a spiritual breakthrough while praying. Your prayers have more effect if you fast. You should not fast to impress other people but rather you should not let anyone know you are fasting (except your doctor). The Lord wants us to love Him, to fast, and weep with mourning.

Do not let others know you are fasting.

• ​Moreover when ye fast, be not, as the hypocrites, of a sad countenance: for they disfigure their faces, that they may appear unto men to fast. Verily I say unto you, They have their reward. Matt. 6:16
• But thou, when thou fastest, anoint thine head, and wash thy face; Matt.6:17
• That thou appear not unto men to fast, but unto thy Father which is in secret: and thy Father, which seeth in secret, shall reward thee openly. Matt. 6:18 ​

The Lord wants us to love Him, fast and weep with mourning.

• Therefore also now, saith the Lord, turn ye (even) to me with all your heart, and with fasting, and with weeping and morning: Joel 2:12

When you want big miracles from the Lord fasting is a required.

• Joel 1:13 Gird yourselves, and lament, ye priests: howl, ye ministers of the altar: come, lie all night in sackcloth, ye ministers of my God: for the meat offering and the drink offering is withholden from the house of your God.
• Then I proclaimed a fast there, at the river of Ahava, that we might afflict ourselves before our God, to seek of him a right way for us, and for our little ones, and for all our substance. Ezra 8:21
• For I was ashamed to require of the king a band of soldiers and horsemen to help us against the enemy in the way: because we had spoken unto the king, saying, The hand of our God [is] upon all them for good that seek him; but his power and his wrath [is] against all them that forsake him. Ezra 8:22
• ​So we fasted and besought our God for this: and he was intreated of us. Ezra 8:23 
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​​Fasting can be done in groups in the house of the Lord.

• Joel 1:14 Sanctify ye a fast, call a solemn assembly, gather the elders and all the inhabitants of the land into the house of the LORD your God, and cry unto the LORD,
• Joel 1:15 Alas for the day! for the day of the LORD is at hand, and as a destruction from the Almighty shall it come.

​We should pray and fast for our leaders, ministers, preachers, and teachers.

• Acts 13:1 Now there were in the church that was at Antioch certain prophets and teachers; as Barnabas, and Simeon that was called Niger, and Lucius of Cyrene, and Manaen, which had been brought up with Herod the tetrarch, and Saul.
• ​Acts 13:2 As they ministered to the Lord, and fasted, the Holy Ghost said, Separate me Barnabas and Saul for the work whereunto I have called them.
• Acts 13:3 And when they had fasted and prayed, and laid their hands on them, they sent them away.

​People who hunger and seek righteousness are blessed.

• ​Matthew 5:6 Blessed are they which do hunger and thirst after righteousness: for they shall be filled.

​Fasting when facing death.
When Esther was warned by Mordecci that she and her father's house would be destroyed she and her maidens fasted.

• Go, gather together all the Jews that are present in Shushan, and fast ye for me, and neither eat nor drink three days, night or day: I also and my maidens will fast likewise: and so will I go in unto the king, which is not according to the law: and if I perish, I perish. Esther 4:16

​​Fasting after the crucifixion of Christ.
​Then came to him the disciples of John, saying, Why do we and the Pharisees fast oft, but thy disciples fast not? Matt. 9:14
And Jesus said unto them, Can the children of the bridechamber mourn, as long as the bridegroom is with them? but the days will come, when the bridegroom shall be taken from them, and then shall they fast. Matt 9:15
Married people should refrain from sexual relations when fasting and praying.

• 1 Corinthians 7:5 Defraud ye not one the other, except it be with consent for a time, that ye may give yourselves to fasting and prayer; and come together again, that Satan tempt you not for your incontinency.

​Fast to get prayers answered, to submit yourself to the Lord, and to show you are obedient.
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Isaiah 58:1-14

​Cry aloud, spare not, lift up thy voice like a trumpet, and shew my people their transgression, and the house of Jacob their sins. Isa. 58:1
Yet they seek me daily, and delight to know my ways, as a nation that did righteousness, and forsook not the ordinance of their God: they ask of me the ordinances of justice; they take delight in approaching to God. Isa. 58:2
Wherefore have we fasted, [say they], and thou seest not? [wherefore] have we afflicted our soul, and thou takest no knowledge? Behold, in the day of your fast ye find pleasure, and exact all your labours. Isa. 58:3
Behold, ye fast for strife and debate, and to smite with the fist of wickedness: ye shall not fast as [ye do this] day, to make your voice to be heard on high. Isa. 58:4
Is it such a fast that I have chosen? a day for a man to afflict his soul? [is it] to bow down his head as a bulrush, and to spread sackcloth and ashes [under him]? wilt thou call this a fast, and an acceptable day to the LORD? Isa. 58:5
[Is] not this the fast that I have chosen? to loose the bands of wickedness, to undo the heavy burdens, and to let the oppressed go free, and that ye break every yoke? Isa. 58:6
[Is it] not to deal thy bread to the hungry, and that thou bring the poor that are cast out to thy house? when thou seest the naked, that thou cover him; and that thou hide not thyself from thine own flesh? Isa. 58:7
Then shall thy light break forth as the morning, and thine health shall spring forth speedily: and thy righteousness shall go before thee; the glory of the LORD shall be thy rereward. Isa. 58:8
Then shalt thou call, and the LORD shall answer; thou shalt cry, and he shall say, Here I [am]. If thou take away from the midst of thee the yoke, the putting forth of the finger, and speaking vanity; Isa. 58:9
And [if] thou draw out thy soul to the hungry, and satisfy the afflicted soul; then shall thy light rise in obscurity, and thy darkness [be] as the noonday: Isa. 58:10
And the LORD shall guide thee continually, and satisfy thy soul in drought, and make fat thy bones: and thou shalt be like a watered garden, and like a spring of water, whose waters fail not. Isa. 58:11
And [they that shall be] of thee shall build the old waste places: thou shalt raise up the foundations of many generations; and thou shalt be called, The repairer of the breach, The restorer of paths to dwell in. Isa. 58:12
If thou turn away thy foot from the sabbath, [from] doing thy pleasure on my holy day; and call the sabbath a delight, the holy of the LORD, honourable; and shalt honour him, not doing thine own ways, nor finding thine own pleasure, nor speaking [thine own] words: Isa. 58:13
Then shalt thou delight thyself in the LORD; and I will cause thee to ride upon the high places of the earth, and feed thee with the heritage of Jacob thy father: for the mouth of the LORD hath spoken [it]. Isa. 58:14 (King James Bible Online)

More Bible Verses About Fasting

And she [was] a widow of about fourscore and four years, which departed not from the temple, but served [God] with fastings and prayers night and day. Luke 2:37
[Is] not this the fast that I have chosen? to loose the bands of wickedness, to undo the heavy burdens, and to let the oppressed go free, and that ye break every yoke? Isa.58:6
And it came to pass, when I heard these words, that I sat down and wept, and mourned [certain] days, and fasted, and prayed before the God of heaven, Neh. 1:4

Biblical References for Fasting:
Matthew 9:14-15
Luke 18:9-14

Fasting * Prayer and Reading of the Word:
1 Samuel 1:6-8, 17-18, Nehemiah 1:4, Daniel 9:3, 20, Joel 2:12, Luke 2:37, Acts 10:30, Acts 13:2

Corporate Fasting:
1 Samuel 7:5-6, Ezra 8:21-23, Nehemiah 9:1-3, Joel 2:15-16, Jonah 3:5-10, Acts 27:33-37
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