The source of the info is journalist Blake Hounshell who wrote on this blog that Netanyahu was quote from Maariv journal of wednesday. The Maariv journal is quoting Netanyahu from a speech at Bar-Ilan Univeristy.
https://web.archive.org/web/20080421191330/http://blog.foreignpolicy.com/node/8664

I'm looking for either a scan of the Maariv journal or the footage of the speech. I found Netanyahu's Bar-Illan speech from 2009 but this quote is from his speech in 2008.
https://www.youtube.com/watch?v=NY6fGMC0VtQ