The above clip was taken from an interview given by Shaykh Abu-Ishaq al-Huwayni on the Egyptian satellite television station al-Hikma on 7 July 2011. Al-Huwayni here explains that whoever insults Muhammad, even if he later repents, must be killed.
.... After recounting a hadith regarding Muhammad being mocked by poetry from the Quraysh, al-Huwayni explained that Muhammad "had complete authority to waive his right (to kill those who mocked him).
But the ruler does not have the authority to waive the Prophet's right." Al-Huwayni reported that Muhammad could waive this right whenever he wanted, but after his death he retained this right, meaning no one could waive the right for him. That is why those who insult the Prophet now must be killed. [Translating Jihad] Read more