With just a few weeks until Passover, Penny Faust of the Oxford Jewish Congregation talks about what the festival means.

From parsley dipped in salt water to a delicious mixture of apples, dried fruit and nuts, from unleavened bread to fresh horseradish, the Seder, the Passover meal eaten on the first two nights of the festival, brings its own rituals and ritual foods.

Passover has the most emotional pull of all the Jewish festivals; like Christmas for Christians, it's the time when people go home to celebrate. If they can't, they'll find hospitality in the nearest Jewish community. My four children, on their gap years between school and university, received invitations to Seders in the most far flung places. It's important to share in a Seder wherever you are.

Essentially the Seder (the word literally means 'order') is a celebration of the history of the Exodus, the time when the Israelites, who were slaves in Egypt, escaped to freedom through God's intervention.

You can find the story in the book of Exodus in the Bible; it's a tale of slavery and injustice, contains goodies and baddies, and culminates in the flight of thousands of people after a series of ten plagues suffered by the local people. The plagues were sent by God to persuade the ruler of that time, the Pharoah, to 'let my people go'.

And of course, this story of liberation from slavery became a beacon later on to others, most especially to Africans who were taken to be slaves in America.

The Seder begins with a series of four questions posed by the youngest child asking why we keep the traditions. The rest of the evening is devoted to telling the story of why the Israelites were in Egypt in the first place, how, as economic migrants they became first a threat and then slaves there. And then in the story of the Exodus, how they were liberated from slavery by God. As well as enjoying a festive meal, participants say prayers, sing songs and eat ritual foods to remind them of what it was like to be someone living through those events.

Because we're told not to tell the story as if it happened to 'them' all those years ago but as if it happened to us. Because if it hadn't happened then we would not be here today.

So we eat food dipped in salt water to remind us of the salt tears of the slaves, and horseradish to taste the bitterness of slavery. The mixture of fruit and nuts represents the cement that the Israelite slaves used in building the pyramids of Egypt. And we do not use yeast during the festival; our bread is unleavened because in their flight the Israelites did not have time to let their bread rise.

The legacy of the Passover within the Christian tradition is very strong. Many theologians agree that the Last Supper was a Seder meal emphasising Jesus' commitment to Jewish tradition and practice. And Jesus is called the Lamb of God picking up on the part of the story that says that lambs were sacrificed to provide blood to mark the doorposts of the Israelites so that they avoided the final plague visited on Pharoah and the Egyptians, the death of the first born. The blood of the lambs in this story was life giving.

This year on April 4th the Oxford branch of the Council of Christians and Jews has invited everyone of all faiths and none to participate in a demonstration of this special annual experience.

For Passover has universal relevance in our world today not just for Jews and Christians. Economic migrants are still perceived as a threat in host societies. Slavery still exists.

Once a year Passover reminds us of the arbitrary nature of being a migrant, and the constant occurrence of slavery across the world. It reminds us too that we have a duty both to care for the dispossessed, and to work for the eradication of slavery.