Sitting in the audience was an elderly rabbi, long black coat, elegant white beard. He rose to speak.

"The questions you are asking are good questions, but for this you don't need to come to Chabad. Anyone who has learned Torah can tell you these answers. But you came to Chabad; now let me tell you why you came."

Everyone there was surprised he could speak English; the rabbi with the immaculate black coat and long white beard began his story.

A little boy was walking with his father down a steep hill in the heat of the day. They saw a man coming up the hill towards them, sweating, with a heavy sack on his shoulders weighing him down. When the man reached them the little boy asked what he had in his sack, why he was going up the hill, why he was working so hard.

The man told the little boy that his oven had broken and he had to come down to the valley to get more stones to build himself an oven.

Why not get more stones, asked the little boy, and build a bigger oven that will keep you warmer and you can have more food -- there must be more stones still in the valley? Oh, you little boy, said the man, you don't yet know what it means to have to work, how hard it is to schlep. He put his free hand on the little boy's shoulder. When you'll be big like me you'll be happy with a little oven too.

The little boy and his father continued down the hill.

They saw another man coming up the hill towards them. Same size man, same size sack, but this man didn't seem so weighed down.

What have you in the sack, the little boy wanted to know, is it stones, are you going to build yourself a small oven?

Oh no, the man smiled broadly, no oven building for me! See, I was down in the valley digging for turnips and I hit a treasure. Diamonds! Rubies! Pearls! I have two daughters, two weddings to make, I'm going to open a store and stop peddling from town to town, build myself a house with wooden floors and...

Why not get more diamonds, interrupted the boy, there must be more left in the valley? Son, said the old man putting his free hand on the little boy's shoulder, believe me, I searched the valley clean. I don't think there is another diamond down there.

You see, said the little boy's father, when you're carrying diamonds they're never too heavy. The first guy may have had diamonds too, but he didn't know what they were.

The old rabbi with the long white beard looked at the college kids.

"You see what the father was telling the boy? A Mitzvah is a diamond. Every mitzvah that we do is a precious, precious thing. This is why you come to Chabad; not just to learn a mitzvah but to learn that it is a diamond. When you know they are diamonds then most of your questions will be answered."

I heard this story on a wintry Friday night in Brooklyn. A roomful of Jewish college kids in the early Eighties, challenging the rabbi chairing the roundtable; the questions had shifted with the times: why do we need mitzvahs when we can meditate instead.

You can't be Jewish out of a sense of duty.

I jolted. It was just four weeks since my grandfather died. Rabbi Kazarnovsky was my grandfather.

I type the story with pride and awe. Pride because he was my grandfather; awed because he was my grandfather.

Passion, demands Judaism. You can't be Jewish out of a sense of duty. An observant Jew? an unsatisfying label. Like an obedient child, a dutiful husband, a law-abiding citizen, an "observant Jew" accepts obligations - yet keeps on trudging. I know we're the Chosen People, moans Tevye, but isn't it time you chose someone else?

Duty and diligence are not calculated to inspire, they're heavy rocks. But when duty and diligence are born of passion they are tough as steel and as brilliant diamonds. A heavy load? Maybe, on the scales: but not on my back.

"You have to be a rabbi," a friend told me when I was seventeen, "it's expected of you, it's even in your genes." A duty, he was saying. And I thank a rabbi with an immaculate, long, black coat and an elegant, long, white beard, for showing me it's a diamond