Link to the relevant section of Obama's "A World that Stands as One" speech in Berlin on 24th July 2008:
...which begins:
"This is the moment when we must defeat terror and dry up the well of extremism that supports it. This threat is real and we cannot shrink from our responsibility to combat it. If we could create NATO to face down the Soviet Union, we can join in a new and global partnership to dismantle the networks that have struck in Madrid and Amman; in London and Bali; in Washington and New York. If we could win a battle of ideas against the communists, we can stand with the vast majority of Muslims who reject the extremism that leads to hate instead of hope."