The Fast of Behab: 10 Facts About a Hidden Jewish Tradition

Twice a year, a quiet and lesser-known fast takes place in the Jewish calendar. Known as the Fast of Behab, it is observed on a series of Mondays and Thursdays and carries themes of reflection, prayer, and blessing.

Here are ten key facts to help you understand the Fast of Behab and its meaning.

1. Observed on Monday, Thursday, and Monday

The Fast of Behab is observed mainly in Ashkenazi communities on three days: Monday, Thursday, and the following Monday.

It takes place in the middle of the month of Cheshvan and again in the month of Iyar.

2. Why Monday and Thursday

Monday and Thursday are traditionally seen as spiritually favorable days.

According to tradition, Moshe ascended Mount Sinai on a Monday and descended on a Thursday. These days later became associated with prayer, repentance, and communal gatherings.

3. Why the Fast Does Not Begin on Thursday

Although Thursday is one of the fast days, the sequence always begins on a Monday.

Halachic sources explain that a public fast is not initially set for Thursday. Since Thursday is a busy shopping day before Shabbat, increased demand for food could lead to rising prices.

4. Concern About Rising Prices

Another explanation adds that if people see increased food purchases for a fast, they may assume a drought or crisis is beginning.

This could lead merchants to raise prices. Because Thursday is already a high-traffic shopping day, this concern is especially relevant.

5. Not Observed by All Communities

Although the Fast of Behab is Ashkenazi in origin, not all Ashkenazi groups observe it.

Many Hasidic communities do not fast on these days. Some explain that as the Jewish people move closer to redemption, the need for fasting is reduced. At the same time, certain individuals of high spiritual level continued to observe the fast privately.

6. The Timing in Cheshvan

The Fast of Behab in Cheshvan is observed only after the 17th of the month.

This timing is connected to the beginning of the rainy season. Since one of the purposes of the fast is to pray for blessed rainfall, it is scheduled once the season begins.

Another explanation notes that later in the month the days are shorter, making the fast easier to observe.

7. The Purpose of the Fast in Iyar

In the month of Iyar, the Fast of Behab is connected to agriculture.

It is observed as a prayer for the success of the wheat harvest, asking that the crops not be damaged by heat or decay.

8. Why It Takes Place Early in Iyar

The fast days in Iyar are scheduled toward the beginning of the month.

This is because the 18th of Iyar, Lag BaOmer, is a day of joy. According to many customs, the period of mourning ends around that time, so the fast is held beforehand.

9. Special Prayers Are Recited

Those who fast add Selichot and Avinu Malkeinu to their prayers.

In some communities, especially in the United States, Selichot are recited during the repetition of the Amidah even if not everyone in the congregation is fasting.

10. A Special Blessing for Those Who Fast

On the Shabbat before the Fast of Behab, a special Mi Sheberach is recited in synagogue for those who plan to fast.

Since this fast is not an obligation but a custom, the blessing is said for those who choose to take it on.

Another explanation is that because the dates of the fast are not fixed, the blessing helps remind people of the upcoming fast.

A Custom Rooted in Reflection and Prayer

Although not as widely known as other fasts, the Fast of Behab reflects themes of humility, prayer, and hope for blessing.

Whether connected to rainfall, livelihood, or spiritual growth, it serves as a reminder of the role of reflection and intention in Jewish life.