EVERY seven years in Jerusalem, a remarkable event takes place: Israel's chief rabbis sell the land of Israel to a non-Jew. This is not part of the peace process. Rather, it is the implementation of a legal loophole circumventing a 3000-year-old law.

Under biblical law, every seventh year is a release (Shemittah) for the land of Israel, during which it must lie fallow. "In the seventh year," states the book of Leviticus, "there will be a sabbath of sabbaths for the land, a sabbath for the Lord: your field you shall not sow, and your vineyard you shall not prune."

During the seventh year, produce becomes collective property, serving to feed not only the farmer and his household, butalso the poor. The temporary suspension of normal ownership rights reminds the people that their wealth really belongs to God.
 

THIS conception of property is startling to modern ears - and seems to have been so to ancient ones, too. Even in biblical times, the Jewish people never found the sabbatical laws easy to observe. The prophet Jeremiah identifies failure to keep Shemittah as the reason for the Babylonian exile.

When Jews returned to the land after a much longer exile, in the late 19th century, the question whether and how to revive the principle of Shemittah arose. Faced with limited supplies of food and widespread hunger, the rabbis intervened to prevent the sabbatical year from threatening the viability of nascent agricultural communities. They permitted farmers to sell their land to non-Jews for the duration of the year, and to continue to work it as tenants.

This loophole continues until today. Every seventh year, the Chief Rabbinate of Israel obtains permission from all farmers who wish to sell their land, and then exchanges the farmland for a post-dated cheque from an Israeli non-Jew. At the end of the year, the cheque is returned, and the land reverts to its original owners.

UNTIL recently, the dialogue about Shemittah remained focused on technical arrangements such as these in order to get around the law. In the past few years, however, support for implanting Shemittah in practice has arisen in surprising new quarters.

Non-religious Jews, realisingthe profound environmental and sociological impact that the sabbatical year could have, are now thinking about how it could be revived. This renewed interest has even penetrated the halls of power - a recent conference on Shemit-tah at the Knesset, the parliamentof Israel, attracted law-makersfrom across the political spectrum.

Shemittah's renaissance is not confined to Israelis - or Jews. Last month, I joined Nigel Savage, the founder of the Jewish environmental organisation Hazon, and Shoshana Boyd-Gelfand, the director of the Jewish social-action network JHub, and Canon Giles Fraser, for a panel discussion, "Give It a Rest".

The event, at JW3, a Jewish cultural centre in London, highlighted the increasing relevance of responsible land-use for a world with a growing population and increasingly scarce natural resources.
 

ONE answer to the puzzle of conservation lies in new technology. The constant threat of drought has forced Israel to find new ways to conserve and produce water, from drip irrigation to the reclamation of waste water.

Thanks to a historic agreement between Israel, Jordan, and the Palestinian Authority, that expertise may well prove instrumental in saving a unique feature of the Middle East's natural heritage, the Dead Sea.

Yet the core message of Shemittah is not to overcome nature through technology. In fact, it is the reverse. Shemittah is not supposed to encourage human ingenuity, but rather to highlight our impotence. It serves as a reminder that the fundamental ingredients of agriculture - the dew, the rain, the sun - will always be beyond our control, and to teach us humility in the face of forces greater than ourselves.

It is this sense of humility and respect for our environment that has encouraged grassroots movements in Israel and around the world to see Shemittah as a way of promoting practical principles in the spirit of the law: eating locally grown produce, reducing food waste, and so on. At the same time, more voices are advocating a return to the traditional biblical practice of leaving the land to rest.

Could we really run modern life according to ancient tenets? Strange as it may seem, it would not be the first time. In a society where, as recently as the past century, it was the norm for slaves to work from Christmas to Christmas, it was the notion of a universal weekly day of rest - the biblical edict of the sabbath - that had more impact than any other single institution on preserving the dignity of the individual and improving their quality of life. If the weekly sabbath could have such an impact, why not the sabbatical year?

Shemittah may just be a 3000 year-old idea whose time has finally come.
 

Daniel Taub is the Israeli Ambassador to the UK.