That thorniest of all issues, the Israeli-Palestinian conflict, is on the front burner, so a review of Jewish law on the subject is in order.

Granted, halacha is not monolithic, and it is not closed to interpretation. Different people see the law differently. This is as true in this case as in any other. One thing is not open to interpretation, however: We are commanded to settle the Land of Israel — all of it, not just a piece of it.

So important a mitzvah is this that there even is a rabbinic ruling allowing Shabbat to be violated in order to buy property in the Land of Israel. According to the Babylonian Talmud tractate Bava Kamma 80b, a member of the Bar Pappa family decreed, “the deed of sale may be written even on Shabbat.”

This offended other sages, who attempted an amendment by referencing a ruling made by another sage in a different context. While it is not permissible for a Jew to make the transaction on Shabbat, they said, he or she may ask a non-Jew to act in his or her stead. While to do so in other cases violates a rabbinic prohibition, the mitzvah of settling the Land of Israel takes precedence.

That “amendment” failed to satisfy two of the most authoritative codifiers of Jewish law, who often take opposing views: Rabbi Joseph Karo (author of the Shulchan Aruch), and Rabbi Moses Isserles (the Rema, author of a halachic gloss to Karo’s work).

Ruled Karo, “It is permissible to acquire a house in the Land of Israel from a non-Jew on Shabbat and to sign and register it.” (See Shulchan Arukh, Orach Chaim, 306:11.)

The Rema agreed, but only if the document was written in a language other than Hebrew. That is because writing on Shabbat in a language other than Hebrew “is only a rabbinic prohibition,” which is trumped by the biblical imperative to settle the Land of Israel.

This scandalized Rabbi Yechiel Epstein, author of a commentary on the Shulchan Aruch. A “grave error occurred in the printing of the Shulchan Aruch,” he wrote, adding that Karo meant to adopt the amendment to the Bar Pappa ruling.

In any case, all agree that settling the Land of Israel is important enough to set aside even Shabbat rules.

On the other hand, there is biblical evidence to suggest giving up land is not so great a sin, or may not be a sin at all, if the price is right. Solomon gave 20 cities in the Galilee to Hiram, king of Tyre, yet the biblical text offers no condemnation, probably because of what he got in return: The building materials for God’s House and his own. (See 1 Kings 9:11.)

In the current case, trading land for peace would be worth the price, too, if the “peace” offered is a true peace, one that battles terrorism with vigor; that includes all of the states now opposed to Israel; that has a system that puts peace into practice through such means as trade and tourism.

Entering into this consideration are two “sins” I discussed extensively in my January 8 column: pikuach nefesh (threat to life) and sh’fichut damim (the needless spilling of blood). Pikuach nefesh is considered to be pre-eminent in religious Judaism. Almost nothing — not even Shabbat or the laws of kashrut — takes precedence when life is threatened.

Expropriating Palestinian land to build new settlements puts the lives of the people who move into those settlements in danger. Almost certainly violence will erupt, and blood almost certainly will be spilled. Thus, both pikuach nefesh and sh’fichut damim are halachic factors that must be taken into account.

The same, obviously, is true of a one-state solution, which carries with it the necessity of denying to the Palestinians living in such a state equal status under the law. (Anything else risks having the Palestinians become the majority and voting Israel out of existence.) Aside from the many times the Torah requires that there be “one law” for citizen and all other residents (see, especially, Exodus 23:9 this Shabbat, and also Leviticus 19:34 and 24:22), the Torah also requires Israel to act morally, or risk losing its right to the land. Explained Rabbi Samson Raphael Hirsch, in commenting on several verses in Leviticus 18:

“Just as the people is ‘the people of God,’ so is the land, too, ‘the land of God’….The flowering of the land is dependent on the moral flowering of the people….It is for the fulfillment of God’s will by men of moral purity that each seed germinates, each flower blooms, each fruit ripens….

“Hence, if the society that lives in this land subverts the purpose of its existence by social and moral corruption, the land, too, loses the reason for its existence…, and, in that case, the land will vomit out that society even as any organism will reject an element that has become incompatible with it.”

Finally, even if halacha would seem not to support trading land for peace, we have the word of the Talmud that sometimes the law must be set aside in order to protect the national interest. The consequences of an action must always be considered. (See Rabbi Yochanan’s statement regarding the destruction of the Temple in BT Gittin 55b-56a.)

Some early rabbinic commentators suggested that settling the Land of Israel outweighs all other commandments, but our tradition does not agree. As we recite each morning as a reminder, the study of Torah stands above all other commandments. (See Mishnah Peah 1:1.)

The Torah is clear on life-and-death issues. As Leviticus 18:5 tells us: “You shall keep My laws and My rules, by the pursuit of which man shall live.” Said the Talmud, “shall live by them, not die by them.” (See BT Yoma 85b, BT Sanhedrin 74a, and BT Avodah Zarah 27b, or the Mishnah in BT Makkot 23b for discussions of and exceptions to the meaning of the verse.)

As Samson Raphael Hirsch explained, there are grave consequences when the Torah’s moral laws are ignored: “The land will vomit out that society.”