“The strongest weapon against hateful speech is not repression; it is more speech -- the voices of tolerance that rally against bigotry and blasphemy, and lift up the values of understanding and mutual respect. […] On this we must agree: There is no speech that justifies mindless violence.”

Remarks by the President to the UN General Assembly https://www.whitehouse.gov/the-press-office/2012/09/25/remarks-president-un-general-assembly (25 September 2012), quoted in "President Obama Condemns Both ‘Disgusting’ Anti-Islam Video And ‘Mindless’ Violence Before The U.N." http://www.mediaite.com/tv/president-obama-condemns-both-disgusting-anti-islam-video-and-mindless-violence-before-the-u-n/ by Andrew Kirell, mediaite.com.
2012
Context: In every culture, those who love freedom for themselves must ask themselves how much they're willing to tolerate freedom for others. That is what we saw play out in the last two weeks, as a crude and disgusting video sparked outrage throughout the Muslim world. Now, I have made it clear that the United States government had nothing to do with this video, and I believe its message must be rejected by all who respect our common humanity. It is an insult not only to Muslims, but to America as well. [... ] I know there are some who ask why we don't just ban such a video. And the answer is enshrined in our laws: Our Constitution protects the right to practice free speech. Here in the United States, countless publications provoke offense. Like me, the majority of Americans are Christian, and yet we do not ban blasphemy against our most sacred beliefs. As President of our country and Commander-in-Chief of our military, I accept that people are going to call me awful things every day -- (laughter) -- and I will always defend their right to do so. (Applause.) [... ] The strongest weapon against hateful speech is not repression; it is more speech -- the voices of tolerance that rally against bigotry and blasphemy, and lift up the values of understanding and mutual respect. [... ] On this we must agree: There is no speech that justifies mindless violence. (Applause.) There are no words that excuse the killing of innocents. There's no video that justifies an attack on an embassy. There's no slander that provides an excuse for people to burn a restaurant in Lebanon, or destroy a school in Tunis, or cause death and destruction in Pakistan.