One of the 2002 Bali bombers, Amrozi bin Nurhasin, on trial in an Indonesian courtroom and headed toward execution, shouted out the message he wanted his crime to convey: "Jews: Remember Khaibar. The army of Muhammad is coming back to defeat you."

This was his explanation of the murder of 202 people eight years ago. Of those who died, 88 were Australians, 38 Indonesians, 24 British. None were Jews. So what was Amrozi, a Java-born Indonesian, raving about? It's a question worth considering as we assess the recent arrests for terrorist conspiracy in Ottawa. Islamic terrorists can finds motives in ancient struggles the rest of the world long ago forgot.

Martin Gilbert, the author of some 80 books, including the official biography of Winston Churchill, explains Amrozi's meaning at the start of his alarming chronicle, In Ishmael's House: A History of Jews in Muslim Lands, published last week.