From the foreword to The Pillar of Fire:
A few years ago, at a psychiatric convention, I ran into a girl with whom I studied medicine and with whom I interned in the Neurological Department of one of the municipal hospitals in Berlin. We met in a big hotel in Chicago. It was a most fortunate meeting and we were both overjoyed. We had not met for fourteen years, and had heard little of each other. She had the same halting, absent-minded way of speaking, as if she were always thinking of two things at a time. She looked older and there were lines in her face that had not been there before. There was so much we had to tell each other. While she spoke of her didactic psychoanalysis in Zurich, her marriage, her child, her practice, about mutual friends who had perished in Europe, I was asking myself: “Shall I tell, or shall I not tell?”
If I were to say to her, “Since we last met, I have become a Catholic,” it would be a statement entirely different from any other I could make. We both had many startling and unexpected things to tell; it could not be otherwise with two Jews who had parted in Germany in 1932 and met again in America in 1946. But the fact is that with that simple sentence, “I have become a Catholic,” there arises a cloud of estrangement. No matter how much one attempts to break this estrangement down to the elements of social or political separation, of prejudices from childhood, and so on, there is something additional which cannot be explained so easily. What is it?
While the conversation was as far removed as possible from speculations of this kind, I told her of this decisive event in my life. She paused for a moment and then said simply and shortly: “Oh!” Her polite exclamation contained a cosmic abyss. It is about this “Oh!” that this book is being written.
When I meet a friend with whom I used to work in the Zionist Youth Movement or in a group of radical students, I realize the extraordinary fact that, when we come to the bottom of things, I have not really departed from their ideals. There is a core to their beliefs which I still share with them. It is contained in my belief. What must appear to them as a betrayal, is to me a fulfillment. I still understand everything they are talking about, but they cannot possibly understand me. This is what makes these scenes, as human encounters and as meetings of friends, so agonizing. We talk about the Histatrut (the Labor Unions in Palestine), about the Poale Zion (left wing Zionism), the Kibbuz (the movement of cultivation of the land in Palestine, without private property), about my brother who lives as a teacher in one of those co-operative settlements, or of old friends who were killed as Trotskyites, as Social Democrats, or simply as Jews — and then it comes.
“What has happened to you?”
“I have become a Christian.”
Some of my friends even pale and their pupils dilate. A common world falls asunder.