The debut of Abi Al Hassan Muhajer came in a 24-minute speech posted on social media. Replete with verses culled from the Koran and paragraph-long quotes from religious scholarly texts, it acknowledged the "hardships" facing Islamic State, which has been battered in recent months by attacks from a long list of foes, including Russia and the United States.
Yet he insisted that the Sunni Muslim extremist group had faced more difficult obstacles in the past and had emerged in their aftermath "stronger in determination and harder in strength."
He railed against "crusader America and Europe, Communist Russia, and Persian Iran," as well as "the sacrificial goats," a reference to the Shiite, Kurdish and other Sunni militiamen battling to oust the jihadists from bastions overrun during Islamic State's heyday in 2014.
The fight to destroy the extremist group has made uneasy bedfellows of longtime adversaries, including the United States and Iran, and the U.S. and Russia, even while creating new tensions between established allies like the U.S. and Turkey.
"Their slogan is one: 'Destroy Islam and its people,'" Muhajer intoned before urging the group's soldiers in Iraq and Syria to repulse attacks on Tall Afar, Iraq, and the Syrian cities of Raqqa and Al Bab.
The three cities. all held by Islamic State, along with its de facto Iraqi capital of Mosul, form the backbone of its its self-proclaimed caliphate.
Mosul has been the target of a major assault by the Iraqi military and Kurdish militias, with support from U.S. forces.
Tall Afar, located roughly 40 miles west of Mosul, is a vital gateway that opens into the oil-rich desert region straddling the borders of Iraq and Syria. In recent weeks, Iraq's Popular Mobilization Units, Shiite-dominated militiamen working under Baghdad, have surrounded Tall Afar. Its takeover would establish what officials describe as a "killbox" that would eliminate jihadists' fleeing Mosul to Raqqa.
The U.S. has also pushed its top ally in Syria, a loose, Kurdish-dominated alliance of armed factions known as the Syrian Democratic Forces, to mount a campaign for Raqqa. Turkey, backing its own group of Syrian rebels, has its eyes set on Al Bab, 87 miles northwest.
Muhajer reserved special ire for Turkey and its leader, President Recep Tayyep Erdogan, whom he called "the beggar before the doors of crusader Europe."
"Kill Turks wherever you know they are present and seek them by every means, above every earth and below every sky," he commanded.
Turkish government military, economic and even media entities were specifically to be targeted, he said, as well as "every [Turkish] embassy and consulate ... in countries all over the world."
Little is known about Muhajer, whose first appearance comes more than three months after the death of Abu Mohammad Adnani, the longtime top proselytizer and chief strategist of the group. He was killed in a U.S. airstrike on Al Bab in late August.
Yet Muhajer's delivery shows an agitator cut from the same cloth. His speech was peppered with the inflammatory rhetoric and rambling religious asides that were Adnani's calling card.
And like his predecessor, he urged the group's disciples in the West to conduct so-called "lone wolf attacks," solo kamikaze killing sprees conducted by those with no overt links to Islamic State.
"Know that in your blessed operations there is a tipping of the scales… attack them in their homes, markets, roads and clubs," he said.
"Set ablaze the ground beneath their feet."
Bulos is a special correspondent