MONTGOMERY, Alabama (CNN) -- Alabama's chief justice, bucking his fellow state Supreme Court justices and a federal judge, will turn again to the nation's highest court in his fight to keep a monument to the Ten Commandments in the state judicial building.
"The people of this state elected me as chief justice to uphold our constitution, which established our justice system on invoking the favor and guidance of almighty God," Chief Justice Roy Moore said Thursday. "To do my duty, I must acknowledge God. That's what this case is about."
U.S. District Judge Myron Thompson had ordered Moore to remove the monument by midnight Wednesday. Moore refused.
On Thursday morning, the Alabama Supreme Court's eight associate justices overruled Moore and ordered the 5,300-pound monument removed "as soon as practicable."
"The refusal of officers of this court to obey a binding order of a federal court of competent jurisdiction would impair the authority and ability of all of the courts of this state to enforce their judgments," the eight associate justices ruled.
Later Thursday, Moore told cheering supporters he would file a formal appeal with the U.S. Supreme Court to overturn that order. The court has so far refused to block the removal.
Moore said he was "very disappointed" in colleagues who directed court administrators to have the monument removed. But the justices said Moore is legally bound to follow a lawful court order even if he disagrees with it.
Moore's supporters have held round-the-clock prayer vigils outside the judicial building. As Moore prepared to speak Thursday, they sang the civil rights anthem "We Shall Overcome" on the building's steps, located a block from the church where Martin Luther King Jr. once preached.
The Rev. Pat Mahoney, leader of the pro-Moore Christian Defense Coalition, called Thursday's order an act of "judicial tyranny" and "the crushing of the First Amendment."
"We will peacefully and prayerfully kneel around this court building, risking arrest, should they try to remove this monument," he said.
But Ayesha Khan, a lawyer for Americans United for Separation of Church and State, said Moore has "loudly and vociferously" acknowledged his purpose in having the monument put in was to "proclaim the sovereignty of the Christian God."
"The Ten Commandments are a holy document. They are a sacred document," she said. "They are personal and it shows a profound disrespect for them -- and for the federal courts and for religion -- for them to become the star attraction in a three-ring circus."
Thompson has ruled the monument -- which Moore had installed in August 2001 without consulting the other justices -- to be an unconstitutional promotion of religion. The U.S. Supreme Court has so far refused Moore's requests to intervene.
But Moore said he would be violating the dictates of his conscience if he agreed to remove the monument.
"I hear others talk of a rule of law," the chief justice said. "If the rule of law means to do everything a judge tells you to do, we would still have slavery in this country. If the rule of law means to do everything a judge tells you to do, the Declaration of Independence would be a meaningless document."
Moore was a circuit judge in Etowah County, northeast of Birmingham, in the late 1990s when he fought a lawsuit seeking to remove a wooden plaque depicting the commandments from his courtroom.
The legal battle propelled him to statewide office in 2000, when the Republican jurist was elected chief justice after campaigning as the "Ten Commandments Judge." He had the 5,300-pound granite monument installed in the building housing the state appellate courts in August 2001, and a lawsuit ensued shortly afterward.
Alabama's senior associate justice, Gorman Houston, said last week the justices would take "whatever steps are necessary" to avoid Thompson's threatened $5,000-a-day contempt fine if the monument remained in place. Thursday's order followed a special conference of the eight associate justices, who unanimously ordered the monument's removal.
Alabama Attorney General Bill Pryor, a fellow Republican who has been nominated for a federal judgeship, applauded the justices' order and said it may help prevent the state from piling up a contempt fine.
"The rule of law means that no person, including the chief justice of Alabama, is above the law," Pryor said.
Moore's stand has drawn comparisons to former Alabama Gov. George Wallace, a blustery segregationist who engaged in similar face-offs with federal courts. But in a CNN interview Wednesday night, Moore rejected that comparison.