Jesus was an ingrate,” Peter Leithart writes, and he thinks we should be thankful that he was. So were the Protestant Reformers. Indeed, much of the modern world is in debt to the revolutionary power of Christian ingratitude. That, in any case, is the counterintuitive thesis of Leithart’s provocative new book. Sentimental reflections on the importance of gift giving are a common way to combat modern cynicism, but Leithart will have none of that. In fact, if the power of generosity is often thought to be one of the great heritages of Western history, Leithart’s book can be seen as one long act of ingratitude. Sometimes, Leithart seems to be saying, it is more blessed to reject than to receive.