The day before the new au pair arrived, my father took me aside. "Gideon, be kind to her," he said, "for remember, you were once a stranger in the Land of Egypt." I was only five years old at the time, and I was bewildered by his words, but from his tone, I understood that his message was urgent. I was growing up in the shadows of the Holocaust and he was giving me my first lesson in tolerance and the importance of kindness to strangers.