The vision of the valley of dry bones (Ezekiel 37), which we read in the middle of Pesach, is famous for its promise of resurrection and hope. But God's word has depths and nuances. Let us see what else Ezekiel's vision tells us.

The prophet addresses the bones in God's name, telling them that they will receive His spirit and live, and that God will provide them with sinews, flesh and skin. At Ezekiel's bidding, the bones twitch into life and snap together. Skeletal limbs clatter and regroup, sinews twine around them, flesh blossoms forth and sheets of skin crawl down the bodies. But the valley still lies in the shadow of death. The bodies are whole, but they lie quiet, cold and quiescent.

So God tells Ezekiel to summon the spirit "from the four directions of the world". The spirit comes upon them and they stand up as a "very, very mighty army". And, lest we think that this is just some extraneous group that we can watch and admire, God drives the message home: "Son of man! These bones are all the house of Israel!"

Let us look at ourselves in the mirror of Ezekiel's prophecy. The prerequisite for attaining fulfilled Jewish nationhood, it seems, is this mysterious spirit. Without it, we are a nation of cadavers. With it, we are a colossal, unstoppable force. The spirit is not something that comes from heaven. Ezekiel is told to summon it "from the four directions of the world". The suggestion might be that the spirit has somehow dissipated away from the dead bodies in the vision - from us – into the world. We need to get it back. But what is it?

The prophet Isaiah gives us another glimpse of God's spirit: "Let My spirit which is on you and the words which I have put in your mouth never depart from your mouth and the mouths of your descendants" (59: 21). God's spirit is somehow allied to His word. We can perhaps understand this more deeply by recalling that the Hebrew word for spirit, ruach, also means wind. A spirit is something that moves along like the wind, and, if we allow it, it can bear us aloft. Isaiah's prophecy reminds us never to abandon God's word and to allow ourselves to be moved by it.

This enables us to better understand the vision of the spirit converging on the bones. Ezekiel has a vision of the Jewish people made physically whole, perhaps even established in their homeland with all the trappings of statehood, but lacking a spirit because that spirit has travelled out to the four corners of the world and is not within us. And in this, Ezekiel speaks to our generation in a trenchant way.

To be sure, says Ezekiel, Jewish people have spread God's spirit far and wide. We are blessed with many dedicated and courageous groups and individuals who have taken it on themselves to spread and publicise the Jewish spirit, creating a wind of change in the world. We have Jewish groups tackling racism, homelessness, climate change, poverty, religious prejudice, injustice. We have taken the motive power of Judaism and spread it abroad in the world.

These are marvellous achievements. Jewish outreach was unthinkable 300 years ago, when our forebears were hard pressed to feed and clothe their families, and ghetto walls cast long shadows over us. These people have shown that, despite centuries of dehumanising experiences, we can still exert an exceptional humanising influence on the world.

But this work, necessary and valuable though it undoubtedly is, does not represent the sum total of Judaism. It is supposed to be an expression of and an adjunct to the spirit of Torah within us. If the spirit we share so readily does not move within us too, then for all the life that we spread in the world, we will ultimately lose our Jewishness, functioning as humanists perhaps but not as Jews. As much as we yearn to stride across the world stage and cure the ills of our fellow humans, so we must strive to improve ourselves, zealously righting wrongs and correcting inconsistencies in our own inner worlds. Failing that, the Jewish army will dissipate and lose its spirit, will falter and fail in its bid to do good.

This precious spirit is hard to describe because of its very privacy. It does not need websites or brochures. It comes in forms that even the 21st-century has difficulty comprehending: the stillness that descends as the computer screen darkens and Shabbat candles glow; the tear that prickles an eye on Yom Kippur; a kitchen stocked with kosher food because even eating is one of the ways we show our love for God; a pair of tefillin that are dull with use, yet shine with holiness from all the prayers that have been said with them - these are some of the guises that the spirit takes as it moves within us.

Ezekiel's Pesach message complements the Exodus story perfectly. As our ancestors left Egypt in triumph and marched towards the Promised Land, they must have been an awesome sight, a caravan of two million people striding along behind God's pillar of cloud. We can go there again, says Ezekiel. We can rediscover the idealism of those first steps across the desert floor, and become a "very, very mighty army", colossal and magnificent, healing mankind and ushering in a new epoch of hope and holiness.

David Lister is rabbi of Edgware United Synagogue