Every so often, we hear of a well-meaning Christian attempting a “Jesus Fast” – a forty-day renunciation of food that recalls the time Jesus spends in the wilderness (cf. Matt 4:2; Mk 1:13; Lk 4:2). Undertaking this fast sometimes leads to health issues and even death (a quick internet search reveals a surprising number of such unfortunate incidents). What these strict attempts at messianic replication miss, however, is the fact that “forty” has a specific symbolic meaning in Jewish thought; the number signifies a period of judgment, so that the Gospels’ reference to forty days is more about the nature of Jesus’ testing than it is about calendrical time. In assigning “forty days” to Yeshua’s fast, the Gospel writers locate their Messiah within a numerical Jewish tradition that highlights his experience as the subject of proper judgment.

Jesus’ forty days in the wilderness recalls Israel’s forty years in the Sinai desert after the exodus—a time that Scripture refers to explicitly as a period of divine judgment or testing of the peoples’ faithfulness: “The Lord your God has led you these forty (ארבעים; ‘arba’im) years in the wilderness, that he might humble you, testing (נסה; nasah) you to know what was in your heart, whether you would keep his commandments or not” (Deut 8:2). In his dialogue with the devil, Jesus quotes the very next verse in Deuteronomy (Deut 8:3; cf. Matt 4:4; Lk 4:4), which shows that Jesus’ forty days accomplishes the same end as the Israelites’ forty years: Yeshua is “tested” (πειράζω; peirádzo) in order to see whether he would keep God’s commandments—and, of course, he does.

Beyond the forty years that Israel spends in the wilderness, it does not take much scriptural study to see that the number forty symbolizes judgment: God judges the earth with the flood rains for “forty days and forty nights (ארבעים יום וארבעים לילה; ‘arba’im yom v’arba’im laylah; cf. Gen 7:4, 12, 17; 8:6); Moses, like Jesus, fasts on Sinai for “forty days and forty nights” as he receives the legal statutes of the Torah (Exod 34:28), which would be the standard for “righteous judgment” (משׁפט צדק; mishpat tsedeq; Deut 16:18); and Deborah, the best judge in Israel’s history, brings peace to the land for “forty years” (ארבעים שׁנה;‘arba’im shanah; Judg 5:31; cf. 3:11; 8:28). In light of this numerical symbolism, the meaning of “forty” is far more important than the number itself. Therefore, instead of testing the limits of our bodies with a literal forty-day fast, Bible readers should focus on the theological testing to which the number forty points. Understanding forty days/years as a time of judgment highlights the reason for Jesus’ wilderness wanderings and the level of Jesus’ success in following God.



  1. I love these short blogs. I never read this before and I have never done a long food fast. I've done short fasts and fasted from things, sometimes permanently for Jesus. Prayers and encouraging my Christian brothers and sisters seems more useful.
  2. Dr. Nicholas, thanks for this insight. Would that signify Adam's forty day praying & fasting penitence to hashem in the river jordan also.
    • Adam's fast occurs in the pseudepigraphical "Life of Adam and Eve," but yes. Forty would have a similar valence in this case as well.
    • Thanks for your question, Donald. While we're unsure exactly which year Jesus died (so it may not be a perfect 40 years to the destruction of the Temple), the Talmud states that Rabbi Yochanan ben Zakkai predicted the destruction of the Temple forty years before it happened (not unlike Jesus' own declaration), so "forty" in this case would be a term of judgment prior to destruction (see b. Yoma 39b).
  3. Your teachings that I've read have been greatly appreciated. I've shared them with many others. I am not able to do a class at this time. Please continue to share the biblical teachings of how the Jewish people interpret scriptures. Thank you. GOD bless.
    • We could certainly do something on the commandments, Dee. It's a vast topic; is there something particular that you're wanting to study in more depth?

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    • Israel Bible Center equips you with the tools you need to enter into the Jewish world of Scripture. We provide first-rate teaching, and the opportunity to learn from some of the world’s top scholars. As a student, you will be able to interact personally with our teaching faculty, and gain access to hundreds of hours of Bible courses, including The Jewish Gospel of Matthew and The Hebrew Psalms: How To Worship God. Become a part of the community of teachers and students at Israel Bible Center today!
  4. True the number may mean judgement, but, the time (days, months, years) given is still the literal duration of time expended; 40 days means exactly 40 days not 39, not 41, but 40.
    Why do you always make everything so confusing.
  5. I know quite a few people who have fasted 40 days with no ill-effects at all. Surprised to hear people have suffered physical problems from this.
    • What doctor Nicholas is saying is true, the people you are talking about might be breaking every night. There is no way they can fast for 30 or 40 days without food or water. Your body can take it for 7 to 10 days. So don't try it.

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  6. Thanks for the clarification. Like you rightly said, many so called Christian leaders call for and wind hook their gullible congregations to engage in 40 days fast so that God will answer them and grant their heart’s desires. At the end, nothing to write home about. All for nought!
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