"We swear by the almighty Allah we will never stop fighting you until you leave us alone: We must fight them as they fight us, an eye for an eye, a tooth for a tooth."
This was Michael Adebolajo, age 28, born in Britain to a devoted Christian family of Nigerian background.
His hands covered with the blood of a young off-duty British soldier, he and a younger accomplice made no effort to flee the scene of the crime. The video of the attack, on a busy street in daylight, spoke of both derangement and audacity.
"I apologize that women had to witness this today, but in our land our women have to see the same," Adebolajo said.
The reference to "our land" appeared to confound the first wave of commentary last week.
Muslims had no trouble recognizing the reference. The man of British birth claimed the lands of Islam as his own.
Many decades earlier, Sayyid Qutb, the Egyptian thinker who was the Lenin of the political Islamists (and executed in 1966 by his country's military dictatorship), resolved this tension for generations to come.
We may carry their nationalities, he wrote of infidel nations, but we belong to our religion.
The coldbloodedness of the scene in London recalled another, in the streets of Amsterdam on Nov. 2, 2004.
Mohammed Bouyeri, a 26-year-old Moroccan-Dutchman, had caught up with the filmmaker Theo van Gogh, who was riding his bicycle on a bleak Amsterdam morning.
Bouyeri shot Van Gogh in the stomach, then cut his victim's throat, as though slashing a tire, one witness said. Van Gogh had pleaded for mercy: "Don't do it, don't do it."
There was no mercy on offer.
Bouyeri wasn't quite done. He pulled out a smaller knife and pinned it to Van Gogh's body with a letter attached.
Nor was there any remorse at his trial. Bouyeri didn't recognize the authority of the court. He lived by the law of the Islamic Shariah, he said.
Fittingly for this disordered world, Bouyeri wore Nike sneakers under his black djellaba. He spoke no Arabic and very little if any Berber. He knew little of Islam.
His turning to the faith was sudden. Until then, he had been "Mo," cheerful and clever at school. (Ian Buruma gave a superb account of this crime in his 2006 book, "Murder in Amsterdam.")
The assimilationist promise of the polyglot societies of the West has come under intense challenge. A second generation of disaffected Muslims has risen.
The charges that MI5, Britain's domestic intelligence agency, had failed to foresee the danger the assailants posed are predictable, but futile.