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The Use of Signs and Omens in Predicting the Future

  • Rav Moshe Taragin

The first Mordekhai in masekhet Yoma questions the permissibility of eating "simanim."  These foods are meant to evoke/indicate, through their symbolism, positive experiences for the upcoming year - e.g., eating the head of a fish so that we will merit a quality year (head = good fortune).  After all, the Torah prohibits the use of signs and omens through the prohibition of "lo tenachashu" - one may not resort to signs [Vayikra 19:26].  This article will study the parameters of this issur and, ultimately, the specific question posed by the Mordekhai.


            Possibly a good source with which to begin our inquiry is the machloket between the Rambam and the Ra'avad (Hilkhot Avodat Kokhavim u-Mazalot 11:5).  The gemara in Sanhedrin (65b) cites two different beraitot defining the biblical prohibition of using omens.  The first beraita lists such common omens as food falling from one's mouth or a deer crossing one's path.  The second beraita lists studying the conduct, communication, or migratory patterns of fish or birds.  The 'events' listed in the first beraita as well as the 'natural phenomena' of the second, were elements which were classically used as omens to predict the future.  The Rambam includes these omens within the prohibition but extends the issur to include any and every sign used to predict the future - even a personal one.  For example, the Rambam claims that it is forbidden for someone to determine his future actions based on personal episodes.  One mustn't say 'if the following occurs I will take a specific action and if not I will refrain.'  This activity - practiced by Eliezer (by suggesting that he would select a bride for Yitzchak based on the generosity extended to him by the well) is forbidden.  The Ra'avad argues with the Rambam and claims that these personal signs and determinants are permitted.  We must question why the Ra'avad views these as distinctly different from classical omens.  Shouldn't any attempt to predict the future be a violation of the issur of nichush?


            The Radak in his commentary to Shemuel (I 14:9) offers an explanation to the Ra'avad's position.  In this perek of Shemuel we witness Yonatan basing his decision upon a 'personal sign.'  He instructs his arm's bearer: "If the Pelishtim will respond to our beckoning by saying 'Come up to us,' we will attack for it is a sign that we will certainly be victorious.  If, however, they order us to stop, we will not continue with our attack."  Isn't this in violation of the prohibition of lo tenachashu?  The Radak answers that the issur applies only to signs which were employed by professional seers to help predict the future.  Once these signs became institutionalized they were forbidden.  However, individual signs which a person sets for himself are completely permissible and were employed both by Eliezer and Yonatan.


            Evidently, the Ra'avad (according to the Radak's explanation), understands the prohibition very differently from the Rambam.  According to the Ra'avad, the prohibition of nichush stems from the general category of kishuf - black magic and sorcery which dominated the ancient world and, particularly, the land of Cana'an.  The association between nichush and kishuf can easily be seen in parashat Shoftim which lists nichush alongside other activities of black magic such as consulting the dead, speaking to bones, sacrificing to the molekh, making wounds in the skin, actual kishuf etc.  The Ran in his commentary to Chullin (95b) actually refers to nichush as darkhei ha-Emori further testifying to the association between these issurim and the world of avoda zara.  By contrast, the Rambam might have maintained that lo tenachashu is an independent issur and therefore its scope is not limited to activities practiced by ancient pagan sorcerers, but even includes personal signs.


            An additional machloket regarding the scope of this issur which might also shed light upon the nature of the issur can be seen by examining the Chidushei ha-Ran on Sanhedrin (65b) which quotes the opinion of the Rabbenu Dovid.  [Rabbenu Dovid was a talmid of the Ramban.  Unfortunately, we only have possession of his commentary to masekhet Pesachim.  However, his views are cited by many Rishonim, particularly by the Ran.)  He claims that the issur only applies to those who consult MEANINGLESS signs (such as those examples cited in the gemara - bread falling out of one's mouth and a deer crossing the path etc.)  Those who consult authentic systems, which can indeed provide a glimpse of the future, do not violate this issur.  He mentions medieval astrology which he believed was capable of foretelling future 'situations.'  Rabbenu Dovid claims that events themselves are not predetermined, but tendencies and proclivities do exist.  Nonetheless, a person maintains the free will to counter these situations or tendencies.  He cites a gemara in Pesachim (113a) to support his view.  The gemara asserts that one who contemplates the stars to help determine the future violates a positive commandment of "tamim tihiyeh im Hashem Elokekha - You should be complete / pure in your belief of God" [Devarim 18:11] (not feeling compelled to predict the future).  Rabbenu Dovid deduces from this gemara that by gazing at the stars the ISSUR of lo tenachashu is NOT VIOLATED, rather a positive commandment hasn't been kept.


            Interestingly enough, the Ramban takes a diametrically opposed view of this issur.  Indeed, there are many systems employed by ancient cultures to predict the future.  One such manner is astrology but the Ramban also recognizes the migratory patterns of the birds and the fish as events which can help disclose the future.  In fact, according to the Ramban, these events were not even prohibited to the general public but instead were viewed as sciences.  By contrast, necromancy and black magic are referred to as 'to'eiva' and led to the resident Cana'an nations being expelled from Israel.  Nichush, however, is not a to'eiva but a chokhma and completely permissible to Gentiles.  In his assessment of these systems, the Ramban is indeed similar to the position of the Rabbenu Dovid.  According to the Ramban, however, it is PRECISELY these 'legitimate' systems (and not the vacant ones) which are forbidden to Jews.  As the parasha itself in Shoftim describes, we are privileged to merit a prophet who can relay the direct word of God and, hence, have no need for these subsidiary and inferior systems of predicting the future.  In addition, as the pasuk itself suggests, tamim tihiyeh im Hashem Elokekha - our association with, and faith in, God should be so sturdy that we are not obsessed with the fear of the fixture.


            The Ramban and the Rabbenu Dovid argue as to whether the issur applies only to vacuous systems or specifically to legitimate ones.  This machloket of scope might also reflect different opinions as to the nature of the issur.  If the issur is based upon black magic and avoda zara, it might not apply to a legitimate system.  If, however, the issur stems from a lack of faith in Hashem it might apply specifically to authentic systems.  According to the Ramban, the gemara which claims that by consulting the stars a person violates the commandment of tamim tihiyeh is in effect addressing our very issur of lo tenachashu!!!  Essentially, the issur of lo tenachashu and the mitzva of tamim tihiyeh overlap.





            We have examined the scope of the issur as a means for indicating its nature.  According to the Ra'avad, the issur applies only to conventions practiced by ancient seers; evidently, the issur stems from the world of avoda zara.  Though the Rabbenu Dovid slightly disagrees with the Ra'avad in terms of scope (and extends it to any vacuous system - even if not practiced by ancient cultures) he might still define the issur in terms of avoda zara/black magic and thereby limit it only to meaningless systems.  By contrast, the Ramban (and possibly the Rambam) by extending the issur to any attempt to predict the future - even authentic ones might have viewed the issur as deriving from a lack of faith in Hashem.


            This question might suggest an additional halakhic ramification.  Would a Gentile be forbidden to utilize nichush?  This issue is dealt with by the Kesef Mishneh (in his commentary to the Rambam ibid. and by the Me'iri to Sanhedrin 56b).  Clearly, if the issur stems from the world of avoda zara there might be room to prohibit a Gentile as well (though we might question which aspects of avoda zara apply to a Gentile.  At least the 'feasibility' of extending the issur applies).  If, however, the issur derives from a lack of 'higher' faith and commitment to Hashem, we would surely limit the issur to Jews (as the section in Shoftim suggests).  Obviously, this issue greatly influences the way we understand the section in parashat Chaye Sara in which Eliezer appears to use a sign to determine the appropriate woman to marry Yitzchak.


            This question, and in particular the Ramban's view of the issur, might assist us in understanding a startling position of the Bach.  Tosafot in Chullin (95b) question Eliezer's use of omens in selecting a wife for Yitzchak.  They assume that the issur applies to Gentiles as well (since nichush is associated with kishuf which according to one position in Sanhedrin is forbidden to Gentiles as well).  Tosafot suggest that Eliezer only proffered the gifts to Rivka AFTER learning of her family connection; in effect he did not RELY upon the omen.  This assertion is textually strained since it clearly states in parashat Chaye Sara that he bestowed the wedding gifts prior to discovering her family (though when Eliezer recounts the episode to Rivka's family he presents it as if he had delayed conveying the gifts until discovering her family).  The Bach in Yoreh De'a siman 179 disagrees with Tosafot's solution and offers an alternative.  Since Eliezer "operated with ru'ach ha-kodesh and placed all his trust in Hashem that the merit of Avraham would assure that Hashem would select a proper bride for Yitzchak through a miracle" - the use of nichush was permitted.


            How might we understand this suggestion?  Indeed, the Sforno in his commentary to parashat Chaye Sara offers a similar opinion.  He claims that Eliezer did not actually look for an omen but instead prayed to Hashem to help him find a suitable bride.  Effectively, he asked Hashem directly to 'deliver' this woman and inform him through the use of a sign.  According to the Sforno, Eliezer was not actually making a decision based upon an omen, but deferring the decision to Hashem.  According to the Bach, however, it would appear that Eliezer did actually form his own decision and did rely upon the sign but since he was using ru'ach ha-kodesh it was permissible.


            Quite possibly, the perspective of the Ramban would form the basis of the Bach's position.  If indeed nichush is a form of avoda zara there would be no special permits allowed.  If, however, it displays a lack of trust in Hashem, no issur would apply if the person is operating under ru'ach ha-kodesh and trusts that whatever sign might occur is really a communique directly from Hashem.  Indeed, Eliezer utilized this sign, but it was permitted because in his exceptional case it did not display a lack of "tamim tihiyeh im Hashem Elokekha."






1. Examine the pesukim which serve as the source for a mitzva/issur. The description of lo tenachashu in Kedoshim differs from the description in Shoftim.  Each parasha might suggests a different view of the issur.


2. The scope might reflect the essence.  By questioning the systems of prediction which are forbidden we might be able to determine the nature of the issur.


3. Quite often, questioning the relevance of an issur to a Gentile helps determine its essence.  Gentiles are only commanded in seven principle mitzvot.  If a particular halakha applies to a Gentile as well, we would be forced to categorize the mitzva as a subset of one of these seven.






1. In terms of the simanim we eat on Rosh Hashana the Mordekhai answers that these are permissible since they appear in Tanakh and midrashim.  How might we explain this answer?


2. Obviously, this shiur touches upon several practical issues from astrology, to opening a chumash to help make a decision, to flipping a coin (heads or tails).  The shiur is not intended as a halakhic discussion but rather to elaborate upon the basic analytical issues which underlie the issur.


3. For those interested in a more thorough analysis of the theme of the issur, recommended reading is an article published in Beit Yosef Sha'ul (NY, Yeshiva University 5749) by Rabbi Elchanan Adler.  Many of the aforementioned sources and ideas appear in this article.