The video mentions Mohammed Bouyeri, who killed Theo Van Gogh, as an example of a successful attack to be emulated.
Via ABC News:
"Muslims in the West have to remember that they are perfectly placed to play an important and decisive part in the Jihad against the Zionists and crusaders, and to do major damage to the enemies of Islam, waging war on their religion, sacred places, and things, and brethren," says Gadahn. "This is a golden opportunity and a blessing."
He claims that many Western born or raised jihadis, the "brothers who came from abroad" are now thinking about returning to their "Crusader" countries to "discharge their duty of jihad." He also says not to worry about imprisonment, since so many have been jihadis have been set free. "If it's Allah's will that you be captured, then it's not the end the world, and it doesn't necessarily mean that you're going to spend the rest of your life in prison." Many mujahideen who were locked up "are now back home with their families, or back on the frontlines, fighting the enemies."