One of the dilemmas which face yeshiva students and seminary girls who come from the Diaspora (outside of Israel) to study Torah in Israel, is how to observe Yom-Tov; should they observe two days as they did in the Diaspora, or one day like the Israelis?

The Torah sages deal directly with this question, and there are many dissenting views. In the following paragraphs, we shall try to present some of the underlying reasons for the differing views.

One of the early Torah sages to discuss this question is the Chacham-Zvi. The Mishna in Messechta Pesachim (50) says that a person that travels from one place to another must practice both the stringencies of the place that he left as well as the stringencies of the place that he arrives at. Although this would seem to indicate that even while in Israel one must continue observing the second day of yom tov, the Chacham-Zvi concludes that this is not the case. Firstly, because it is strictly forbidden for one to recite the blessings and prayers of yom-tov when not obligated - and there is not enough proof found in the Gemara to prove this position beyond a reasonable doubt. Secondly, this Mishna only applies to a very specific case; Namely, to a situation where an entire community has left the Diaspora to permanently move to Israel. In such a situation, we do not want their ancient practices to be lost forever. It is only due to permanent nature of this case that they keep the second day. However, when an individual comes to Israel temporarily, he does not have to keep the second day. Similarly, if an entire community moves temporarily, they don’t have to keep the second day either. Indeed, the Chacham-Zvi goes so far as to indicate that if someone does not move permanently to Israel, observing the second day of yom tov while there would be a violation of the Torah commandment: "בל תוסיף" – "Do not add", a prohibition against adding to the commandments of the Torah (see Rosh Hashana 28).

Another consideration that the Chacham-Zvi deals with is the Gemara (Beitza 4) that states: "שלחו מתם הזהרו במנהג אבותיכם בידיכם" – "They sent from there: Take care to observe your fathers customs". Here too, the Chacham-Zvi asserts that the rule to keep all laws that are followed in the land that one comes from only applies to one who continues to live where his father lived. However, this does not apply when you move, even temporarily, to a new land.

As we see, the Chacham-Zvi is of the opinion that a yeshiva student or seminary girl who goes to study in Israel should observe only one day - as he does not plan to live there permanently. Indeed the Shulchan Aruch of the "Baal HaTanya" accepts this ruling (although he notes that there are differing opinions). Additionally, Lubavitch follows this ruling as well.

However, Maran Rav Yosef Karo, author of the Shulchan Aruch, asserts in his work "Avkat Rochel", that the widespread custom from early times, practiced in the presence of many great sages, was for those who came to Israel with the intention of returning to the Diaspora to observe the second day of yom-tov. Furthermore, they would gather together in public and have a "minyan" for those from the Diaspora, even reading the Torah reading of the Diaspora. Maran Rav Yosef Karo (ibid) attests to the fact that no one ever questioned this practice, and that even the Talmudic dictum of "אל ישנה אדם מפני המחלוקת" – "a person should not act differently than others for this can cause strife" doesn't apply here.

Which opinion should a yeshiva student or seminary girl, who has traveled to Israel, follow? Interestingly, Chacham Ovadia Yosef zt”l rules that in most cases a yeshiva student or seminary girl who has come to study Torah in Israel for several years should observe only one day, since he or she might decide to spend his or her life in Israel. Chacham Bension Aba Shaul zt"l ruled that in many cases they should observe one day, but one must be 18 years old (able to get married) to do so - as only at that time are they considered independent, able to marry, and is there a realistic chance they will stay. This seems to be the consensus amongst most Ashkenazi poskim as well (see "Yom Tov Sheni Kihilchato" chap. 7). All agree that the individual ruling depends on many personal factors, such as the possibility, or intent, of one settling in Israel after marriage, dependence on parental support, and others.

 In summary, this is no simple matter, and it is evident that each individual must consult with his Rav or Rosh-Yeshiva to get a personal ruling, applicable to his unique situation.