This week we begin the cycle of Torah readings again, and read the account of Creation. All peoples have sacred narratives about the Creation of the world - but why do we turn right back to the beginning, again and again each year? Why don't we start our narrative with the first ancestors of our people, Abraham and Sarah?

There are many answers to these questions, one of which is captured in a verse in the last book of the Torah: "Sh'ma! Yisrael Adonai Eloheinu; Adonai Echad" - "Listen! Israel the Eternal is our God; the Eternal is One" (Deuteronomy 6:4).

"Our God is One" - the Creator of the entire world; the God of all the peoples. Our tribal ancestors learnt this lesson painfully. It took them centuries to understand that the God who had made a sacred covenant with our people did not belong to us alone. And so the prophet Amos chided them: "Are you not like the Ethiopians to Me, children of Israel?" (9:7): So Isaiah spoke of a future time when even Israel's oppressors would recognise the Eternal, and receive God's blessing: "Blessed be Egypt, My people and Assyria the work of My hands, and Israel, My inheritance" (21:24b).

Perhaps what is most remarkable about Jewish teaching is that it embraces the awareness that the Eternal is both "our God" - our liberator, lovingly keeping the covenant with His people Israel - and the God of all. But this isn't just a theoretical proposition; the prayers we say every day reiterate it. Evening and morning, following the Bar'chu, the "call to prayer", we recite a blessing addressing the Eternal, first as the Sovereign Creator, second as the God who loves us. And each of the three daily prayer services end with the two paragraphs of the Aleinu; the first of which, traditionally, focuses on the Jewish people's unique relationship with God, and the second, on a vision of the future time when all human beings will recognise the One God.

Significantly, the Aleinu was composed by the rabbis (circa 200 CE) for inclusion in the liturgy that they created for Rosh Hashanah, when they envisioned God as Melech Malchei Ham'lachim, "the King above the King of Kings", enthroned on high, the Judge of all the world. For them, the first day of the seventh month of Tishri was both the New Year for the Jewish people, and the anniversary of Creation. The first prayer book, Seder Rav Amram (c. 860 CE) declares: hayom harat olam, "today is the birthday of the world".

Our prayers acknowledge that Judaism encompasses both universalism and particularism - both an awareness of the universal nature of the Eternal and of our particular covenant with God, and this is reflected on Shabbat and on all our major festivals - but do we? And if we do, have we grasped the implications for how we might practise Judaism?

Pirkei Avot, The Sayings of the Sages, includes in its first chapter these two statements: "Simeon the Righteous was one of the Great Assembly. He used to say: The world stands on three pillars: on teaching (haTorah), and on worship (ha'avodah) and on deeds of loving kindness (g'milut chasadim)" (1:2).

"Rabban Simeon ben Gamliel used to say: The world stands on three pillars: on justice (hadin); and on truth (ha'emet) and on peace (hashalom)" (1:18).

The world stands, in other words, both on the particular framework for life practised by the Jewish people, and on key principles that apply, universally, to all, including the Jewish people: all six elements are integral to Judaism. To emphasise one dimension at the expense of the other is a distortion of Jewish teaching.

So, what are the implications for our Jewish practice? As we think this Shabbat about Creation, and, both, of our unique power as human beings, and our unique role as guardians of the earth, the dietary rules of kashrut seem a good place to start.

Last year, Liberal Judaism published a leaflet entitled Ethical Eating, written by Rabbi Janet Burden. One dimension of kashrut is clear: we are what we eat. Along with the other particular practices of Judaism, what we eat sets us apart. But there is also an ethical dimension to the laws of kashrut: animals are to be killed only for food, not for sport; the prohibition against the eating of milk with meat derives from the Torah's injunction against "boiling a kid in its mother's milk".

If we put kashrut in the context of Judaism's universalist teachings concerning our responsibilities towards the earth and the just and compassionate treatment both of animals and of people, we realise that food cannot be fully kosher if the production of it has involved waste, cruelty, or the exploitation of others.
So a chicken can only be fully kosher if it is also organic and free-range; and foods other than meat and fish, too, need to be ethically "fit": locally produced if, like apples, they grow in this country; or fair-traded if, like chocolate, coffee and tea, they can only be obtained from elsewhere.

On one level, it's very simple: Judaism without universalism ceases to be Judaism; Judaism without particularism ceases to be Judaism; both are fundamental dimensions of the whole.

But, of course, it's never simple. We live in the shadow of the Holocaust. During the years following the Shoah, some Jews have turned their back on the world, while others have abandoned the Jewish people to embrace humanity. And yet after the Shoah, perhaps more than at any other time in our history, we need to live as Jews in the world. Rabbi Leo Baeck, incarcerated in the Terezin ghetto for over two years, was inspired by his experiences there to write: "Every people is a question which God addresses to humanity; and every people... must answer for its own sake and for the sake of humanity... God questions humanity through the peoples."

Elizabeth Tikvah Sarah is rabbi of Brighton and Hove Progressive Synagogue