Fasting in the Bible: From Moses to Jesus

The religious practices associated with Islam - Salat (prayer), Zakat (charity), Fasting, and Hajj - are traced back to Abraham and were practiced by the prophets who followed him, including Jesus. Among these practices, fasting stands out as a continuous and deeply rooted act of devotion found throughout the Bible, from the Torah to the New Testament.

Although the Bible contains no detailed legislative code outlining the mechanics of fasting, it consistently assumes fasting as a known and valid practice. This assumption itself is significant: fasting is treated as an established act of worship, familiar to the faithful long before the time of Jesus.

Fasting in the Torah and the Prophets

The earliest explicit fast recorded in the Torah is that of Moses:

Exodus 34:28

"And he was there with the Lord forty days and forty nights; he did neither eat bread, nor drink water."

This passage makes clear that Biblical fasting, at least in its original form, was complete abstention from food and drink. It was not partial or symbolic - it was total.

Similarly, Elijah fasted forty days:

1 Kings 19:8

"So he arose, and ate and drank; and he went in the strength of that food forty days and forty nights as far as Horeb, the mountain of God."

Jesus Himself followed this pattern:

Matthew 4:2

"And when He had fasted forty days and forty nights, afterward He was hungry."

These examples demonstrate that extended fasting - forty days in some cases - was known among the prophets. The length of these fasts strongly suggests that abstention occurred during the daylight hours, with sustenance possibly taken at night.

Fasting and Prayer of Petition

Throughout Scripture, fasting is closely linked with earnest prayer and supplication.

During the time of Esther:

Esther 4:3

"And in every province where the king's command and decree arrived, there was great mourning among the Jews, with fasting, weeping, and wailing; and many lay in sackcloth and ashes."

Esther 9:31

"To establish these days of Purim at their appointed time… as the Jews had prescribed for themselves and their descendants, concerning matters of their fasting and lamenting."

Daniel fasted while seeking understanding:

Daniel 9:3

"Then I set my face toward the Lord God to make request by prayer and supplications, with fasting, sackcloth, and ashes."

King David connected fasting with desperate petition:

2 Samuel 12:22-23

"And he said, While the child was yet alive, I fasted and wept: for I said, Who can tell whether God will be gracious to me, that the child may live? But now he is dead, wherefore should I fast? can I bring him back again? I shall go to him, but he shall not return to me."

Here we see fasting accompanied by weeping, humility, and earnest appeal to God.

Public Fasts and the Ninth Month

While many fasts were personal vows, the Bible also records organized, communal fasting.

Jeremiah 36:6

"Therefore go thou, and read in the roll… the words of the Lord in the ears of the people in the Lord's house upon the fasting day…"

Further detail clarifies the timing:

Jeremiah 36:9

"And it came to pass in the fifth year of Jehoiakim… in the ninth month, that they proclaimed a fast before the Lord to all the people in Jerusalem…"

Verse 22 confirms the season:

Jeremiah 36:22

"Now the king sat in the winter house in the ninth month: and there was a fire on the hearth burning before him."

This indicates that a fast was observed in the ninth month during winter. Historical reconstruction suggests that during Biblical times a purely lunar calendar was used, placing the ninth month around November in 604 B.C.

Additionally, the prophet Zechariah refers to multiple months of fasting during the Babylonian captivity:

Zechariah 8:19

"Thus saith the Lord of hosts; The fast of the fourth month, and the fast of the fifth, and the fast of the seventh, and the fast of the tenth, shall be to the house of Judah joy and gladness, and cheerful feasts; therefore love the truth and peace."

These fasts were associated with a specific crisis - the Babylonian captivity - and were not necessarily intended as permanent institutions.

The Spiritual Meaning of Fasting: Isaiah 58

The most comprehensive teaching on fasting in the Old Testament appears in Isaiah 58.

Isaiah 58:3-7

"'Why have we fasted,' they say, 'and You have not seen? Why have we afflicted our souls, and You take no notice?' In fact, in the day of your fast you find pleasure, and exploit all your laborers. Indeed you fast for strife and debate, and to strike with the fist of wickedness. You will not fast as you do this day, to make your voice heard on high. Is it a fast that I have chosen, a day for a man to afflict his soul? Is it to bow down his head like a bulrush, and to spread out sackcloth and ashes? Would you call this a fast, and an acceptable day to the Lord? Is this not the fast that I have chosen: To loose the bonds of wickedness, To undo the heavy burdens, To let the oppressed go free, And that you break every yoke? Is it not to share your bread with the hungry, And that you bring to your house the poor who are cast out; When you see the naked, that you cover him, And not hide yourself from your own flesh?"

Here, fasting is not reduced to abstinence from food and drink alone. It includes:

• Avoidance of injustice

• Freedom from anger and quarreling

• Charity and feeding the hungry

• Social justice and compassion

The external signs of humility - sackcloth and ashes - are rebuked when disconnected from sincere reform.

Jesus on Fasting

In the Sermon on the Mount, Jesus does not redefine fasting. Rather, He assumes its practice and warns against hypocrisy.

Matthew 6:16-18

"Moreover, when you fast, do not be like the hypocrites, with a sad countenance. For they disfigure their faces that they may appear to men to be fasting. Assuredly, I say to you, they have their reward. But you, when you fast, anoint your head and wash your face, so that you do not appear to men to be fasting, but to your Father who is in the secret place; and your Father who sees in secret will reward you openly."

Just as in Isaiah 58, the emphasis is on sincerity rather than outward display.

Fasting continued in the early church:

• Acts 10:30 - Cornelius fasting and praying

• Acts 14:23 - Appointing elders with prayer and fasting

• Acts 27:33 - Prolonged abstinence

• 1 Corinthians 7:5 - Temporary abstinence for prayer

Summary of Biblical Fasting

From Moses to the apostles, fasting appears as:

• Complete abstention from food and drink during the daylight hours

• Often associated with a lunar calendar framework

• Closely connected to prayer and supplication

• Accompanied by humility and repentance

• Inseparable from charity, justice, and moral reform

• Condemned when performed for show or hypocrisy

Thus, Biblical fasting is not merely dietary restraint. It is a holistic act of worship - discipline of the body, purification of intention, avoidance of anger and injustice, and active compassion toward the hungry and oppressed.

It is a practice assumed throughout Scripture, deeply embedded in prophetic tradition, and reaffirmed by Jesus - not abolished, but purified of hypocrisy and restored to its sincere spiritual purpose.