It was a fateful clash of civilisations when Ancient Greece and Israel collided. Jews won. Had they not done so, there be no Judaism today and there would almost certainly be no Christianity or Islam.

These events are commemorated on Chanukkah, the eight-day Jewish festival of lights we are celebrating now. They happened 22 centuries ago, when Israel came under the rule of the Alexandrian Empire. After Alexander's death the empire split: the Ptolemies in Egypt and the Seleucids in Syria. Each ruled Israel in turn.

Ancient Greece and Israel were profoundly different. The Greeks excelled at everything visual. The Jews worshipped the invisible God. To Greeks, the Jews were strange and superstitious. To Jews, the Greeks were pagans and idolaters.

The Ptolemies allowed Jews to practise their faith in peace but one Seleucid leader, Antiochus IV, believed in the active Hellenisation of the Jews. It was an act of hubris that was to cost him dear.

Not all Jews were opposed to Hellenism. Some saw it as the future. It was cosmopolitan. Judaism, they felt, was parochial. The glittering achievements of the Greeks seemed to breathe a freer air than the pieties of their own people. Two high priests in particular, Jason, then Menelaus, saw Antiochus as an ally with whose help they could force the pace of cultural change.

They introduced a gymnasium into Jerusalem. Young priests began to spend more time on the body than the soul. They encouraged Antiochus to forbid the public practice of Judaism. They even erected a statue of Zeus in the Temple precincts. They began to offer pagan sacrifices on the Temple's altars. It was deeply provocative. The Jews called it the “abomination of desolation”.

A priestly family, the aged Matthias and his sons, known as the Maccabees, rose in revolt. They won back Jewish independence, cleansed and rededicated the Temple, and relit its candelabrum, the Menorah. That is why to this day we light candles for eight days. Chanukkah means “rededication”.

The military victory was short-lived. Within a century Israel was again under foreign rule, this time by the Romans. It was the spiritual victory that survived. Realising that the real battle was not against an empire but a culture, Jews set about constructing the world's first system of universal education. The effect was astonishing. Although they were later to suffer devastating defeats at the hands of the Romans, they had created an identity so strong that it was able to survive 2,000 years of exile and dispersion.

What history taught them was that to defend a country you need an army, but to defend a civilisation you need schools. In the short run battles are won by weapons, but in the long run they are won by ideas and the way they are handed on from generation to generation. Oddly but appropriately, Chanukkah comes from the same Hebrew root as “education”.

In Britain today we risk undervaluing and misconceiving our schools. We think in terms of league tables of academic results. But schools are more than this. They are the way a civilisation hands on its values across time. When a culture forgets its own values, especially when it thinks they are something we each invent for ourselves, it is about to die — not immediately but inevitably. That is why faith schools have become so popular. They have a strong and distinctive ethos. They honour the past. They create community and continuity. They teach children who they are and why.

Hanukkah tells us that there are two different battles for freedom. One is fought by soldiers, the other by teachers, and it is the second that eventually determines the course of history. When civilisations clash, strengthen schools. The world we build tomorrow is born in the lessons we teach today.

Rabbi Sir Jonathan Sacks is Chief Rabbi of the United Hebrew Congregations of the Commonwealth