David Klinghoffer knew that his new book "Why the Jews Rejected Jesus" would make plenty of people angry.
After all, the Orthodox Jewish journalist argues that Jesus misunderstood centuries of Jewish tradition, twisted it or rejected it outright -- or all of the above. The Apostle Paul, he says, padded his Pharisee resume and may not even have been a Jew.
Truth is, Klinghoffer believes Judaism is "true," in every sense of that unpopular word. But he has discovered that many modern Jews get mad when someone has the chutzpah to openly proclaim that Judaism is rational and built on a binding covenant with God that is linked to eternal salvation.
"The Sinai covenant and its commandments, you see, are not compatible with every lifestyle," he said. "So if you try to tell many Jews that the covenant is still in effect they're going to bristle. They see those commandments as a judgment on their lives."
Klinghoffer paused and chose his words carefully: "If you say that one way of living is right, then that implies that another way of living must be wrong. ... If our beliefs clash, then we can't both be right. People don't like to talk about things alike that."
This weekend, millions of Jews will have a chance to talk about their beliefs and the ties that bind as they begin the weeklong Passover season, which recalls the Exodus from Egypt. This is the most widely celebrated of all Jewish holidays, with friends and loved ones gathering for the familiar rites of the symbolic Seder meals.
What Klinghoffer finds disturbing is that the doctrinal lessons of Passover are incomplete without those taught by Shavuot, a holiday that comes 50 days later. Shavuot recalls the revelation of the Jewish law -- the Torah -- to Moses at Mount Sinai.
Without Shavuot, he said, Passover is meaningless. Without the truth contained in the Torah, Jews have no identity.
Yet few Jews celebrate Shavuot and many hesitate to defend their own faith.
"I think it is interesting that when I speak to audiences of Christians and Jews, it's the Christians who say that they appreciate hearing from a Jew who isn't afraid to be honest," he said. "They don't want to settle for watered-down dialogues in which no one talks about the questions that divide us as well as the truths that unite us."
Klinghoffer's book is making waves because it bluntly states and defends the arguments used by Jews -- from ancient times until today -- as they rejected Christian claims that Jesus was the Messiah and the source of salvation for all humankind. Rather than providing ammunition for anti-Semites, he said his intention was to help traditional Jews and Christians be candid.
For example, Christians have for centuries pondered the unique Jewish role in "salvation history," a mystery often summed up in the familiar statement, "How odd of God to choose the Jews." Meanwhile, Jewish scholars have faced a paradox of their own. As the Jewish intellectual Franz Rosenzweig once said: "Israel can bring the world to God only through Christianity."
Without Judaism, there is no Christianity. But without Christianity, Klinghoffer argues, there would be no Western civilization as the world knows it and, without Christendom, Europe would have remained pagan and almost certainly fallen to Islam.
Despite their many differences, Klinghoffer is convinced that traditional Jews and Christians can find unity on many controversial questions -- from abortion to euthanasia, and many hot moral issues in between. Christians and Jews are supposed to believe that "we can say, with a straight face, that there is such a thing as 'truth,' " he said.
This matters in an era in which many want to blur the doctrinal lines between world religions. Others want to deny the existence of religious truth altogether.
"This raises all kinds of questions," said Klinghoffer. "Who gets to decide what is right and what is wrong? Does God get to play a role in those decisions or do we just put that up to a vote among ourselves? Where does moral authority come from? Do we just pluck it out of the air or does it come from somewhere?
"When we start asking these kinds of questions, Jewish and Christian believers can stand side by side."