Oklahoma educators who refuse to teach students about the Bible could lose their teaching license, Superintendent of Public Instruction Ryan Walters said in an interview with NBC News on Friday.

Walters issued a memo Thursday instructing all Oklahoma schools to teach students in grades five through 12 about the Bible’s influence on the nation’s founding and historical American figures. Schools will also be required to stock a Bible in every classroom.

In an interview with NBC News, Walters said if a teacher refuses to follow the Bible instruction mandate, they’d face the same consequences as one who refuses to teach about the Civil War. The punishment could include revocation of their teaching license, he said, a process that requires a vote by the Oklahoma State Board of Education, which Walters chairs.

“Any teacher that would knowingly, willfully disobey the law and disobey our standards — there are repercussions for that,” Walters said. “So we deal with that on a case-by-case basis, but yes, teachers have to teach Oklahoma Academic Standards and this is absolutely going to be part of them.”

Walters’ new rule on incorporating Bible instruction was immediately criticized by civil liberties and religious groups. The Jewish Federation of Tulsa and the Oklahoma chapter of the Council on American-Islamic Relations both said in statements that Walters is inappropriately promoting Christianity in schools.

Americans United for Separation of Church and State also weighed in. “Walters is abusing the power of his public office to impose his religious beliefs on everyone else’s children,” the group said in an email, adding that it is “carefully assessing options.”

The education department had been working on guidance on using the Bible in classrooms for nine months, Walters said. The agency focused on the Bible because it “is the book that’s under assault,” he said.

A spokesperson from the Oklahoma attorney general’s office said in an email that existing law already allowed teachers to use Bibles in the classroom during instruction and that, “There is no legal authority for a memo from the Superintendent to require content.”

Walters said he feels confident that his order will survive legal challenges because of the justices then-President Donald Trump appointed to the Supreme Court.

“He’s helped provide a path for us to be able to do this as states,” Walters said of Trump. He added that if Trump wins a second term in November, “it will help us move the ball forward, even more so than this.”

This article was originally published on NBCNews.com