There are no set times for how long a person should fast. Let’s look at a few instances of fasting in the Bible and the length of those fasts.

Judges 20:26, “Then all the children of Israel, and all the people, went up, and came unto the house of God, and wept, and sat there before the LORD, and fasted that day until even, and offered burnt offerings and peace offerings before the LORD.” Here, the people fasted for ONE DAY.

Esther 4:16, “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.” Here, the people fasted for THREE DAYS.

1 Samuel 31:13, “And they took their bones, and buried them under a tree at Jabesh, and fasted seven days.” Here, the people fasted for SEVEN DAYS.

Moses (Exodus 34:28), Elijah (1 Kings 19:8), and the Lord Jesus (Matthew 4:1) all fasted for FORTY DAYS.

The purpose and length of the fast should be determined after seeking the guidance of the Lord. He will direct you as to how long He would have you fast. We read in Matthew 6:16-18, “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. But thou, when thou fastest, anoint thine head, and wash thy face; 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.” This teaches us that if and when we fast, it should not be done as an instrument to draw attention to ourselves. This is an act that is led of the Lord and should be done privately. Of course, some others, such as family members and close friends, will become aware that we are fasting, but we should not seek to ‘appear unto men to fast.’

Fasting is, of course, abstaining from food for the purpose of focusing on the Lord. Throughout the Word we see that fasting was a tool to help the Lord’s people seek the Lord’s mind while going through times of stress, difficulties, or needing the Lord’s guidance for a particular purpose. While it is not commanded in the Bible, there may be times where we could benefit by going through a time of fasting. (275.8)

To read more about fasting, I encourage you to click on these Answers From the Book links:

http://answersfromthebook.net/do-we-need-to-fast/

http://answersfromthebook.net/what-did-jesus-mean-in-matthew-916-17-after-the-disciples-of-john-asked-him-why-his-disciples-didnt-fast/

http://answersfromthebook.net/if-you-are-fasting-after-ending-the-fasting-period-is-it-wrong-to-eat-as-much-food-as-you-can/