TEL AVIV — THREE weeks ago, my father was riding on a public bus in Jerusalem’s Armon Hanatziv neighborhood when terrorists from East Jerusalem shot him in the head and stabbed him multiple times. Afterward, as he lay unconscious in the intensive care unit of Hadassah Hospital in Jerusalem, fighting for his life, one question was on my mind: What inspired the two young Palestinian men to savagely attack my father and a busload of passengers?

My father, Richard Lakin, dedicated his life to the cause of Israeli-Arab reconciliation. Ever since moving to Israel from Connecticut in the 1980s, he spent his career teaching English to Israeli and Arab children. Inspired by his experience marching with the Rev. Dr. Martin Luther King Jr. in the 1960s, he became a founding member of Israel Loves Iran, a social media initiative designed to bring the citizens of these two nations closer together. When news of his tragedy broke, many of the Christian, Muslim and Jewish residents of Jerusalem who knew my father and admired his work rushed to his bedside to pay their respects and say a prayer for his recovery. Even Ban Ki-moon, the secretary general of the United Nations, stopped by on his recent visit to Israel.

Watching the well-wishers congregating in the intensive care unit, however, I realized that the world leaders who were having the most impact on the situation in the Middle East right now weren’t Mr. Ban or Prime Minister Benjamin Netanyahu, but Mark Zuckerberg of Facebook, Jack Dorsey of Twitter and other young entrepreneurs who shape the social media platforms most of us use every day.

It may sound strange to talk of Twitter and Facebook as relevant players in the war against terror, but as the recent wave of violence in Israel has proved, that is increasingly the case. The young men who boarded the bus that day intent on murdering my 76-year-old father did not make their decision in a vacuum. One was a regular on Facebook, where he had already posted a “will for any martyr.” Very likely, they made use of one of the thousands of posts, manuals and instructional videos circulating in Palestinian society these last few weeks, like the image, shared by thousands on Facebook, showing an anatomical chart of the human body with advice on where to stab for maximal damage.