A troubling proverb

People here commonly and openly talk about not liking whole other groups of people.

I don't like Saudis, one of our interpreter-applicants told us flatly, for example. I never liked Americans before I met you, a reporter informed us recently. The French, Moroccans, black Africans, Kabilye, members of other regions, religions, countries. The tribal divisions among us are very noticeable in Algeria.

It's an ugly reality that came out in a discussion with editors the other day. One of them used an expression that Nadir, our interpreter, explained was an old Arab saying: "Eat with Jews; spend the night with Christians."

It's nothing racial, the editor told us. Nadir explained that Jews like Arabs have strict dietary rules and cannot eat just any meat. Their kosher rules are much like Muslim halal rules for slaughtering.

OK, that makes sense. What about spending a night with Christians -- they have the same sex rules?

No, Nadir explained on, fidgeting a little. Not sex, spend the night as in stay close to. It's because Muslims have strict rules on bathing and cleanliness and Jews are not regarded as clean. They smell.

What are you talking about, I asked -- THAT is not racial?? "Well I think it is," he said, "but I have to explain it to you. I was kind of sputtering at this point so he called over one of our colleagues to the discussion and he said Nadir had it wrong.

Muslims and Christians share the same high regard for loyalty, he said.

This is even worse -- what does loyalty have to do with spending a night together and does this mean Jews are fickle or feckless? That also sounds prejudiced.

The disturbing conversation went no further. If anyone knows this saying or has more information about the thoughts behind it, I would like to hear them please.