Oklahoma Superintendent of Public Instruction Ryan Walters issued a memo on Thursday requiring the Bible to be taught in public schools for grades 5 through 12.

“The Bible is a necessary historical document,” Walters said in an announcement, “to teach our kids about the history of this country, to have a complete understanding of Western civilization, to have an understanding of the basis of our legal system, and is, frankly … one of the most foundational documents used for the Constitution and the birth of our country.”

He went on to mention how several key documents, such as the Federalist Papers, and figures in America’s history, such as Martin Luther King Jr., reference and build arguments upon the Bible. “It is essential that our kids have an understanding of the Bible and its historical context,” he said.

The letter sent to state school district superintendents said that the mandate is compulsory, and “immediate and strict compliance is expected.”

This comes after Louisiana became the first state to require displays of the Ten Commandments in public school classrooms last week. “If you want to respect the rule of law you’ve got to start from the original law given, which was Moses,” Louisiana Gov. Jeff Landry said at a signing ceremony.

Matt Krause, independent legal and policy advisor to First Liberty Institute, said, “The Pelican State has rightly recognized the history and tradition of the Ten Commandments in the state. Putting this historic document on schoolhouse walls is a great way to remind students of the foundations of American and Louisiana law.”

Oklahoma City television station KOCO says it asked the state’s attorney general, Gentner Drummond, if the order was legal, and he said it is, with Oklahoma law allowing teachers to use the Bible in their instruction. However, Drummond didn’t specify whether teachers can teach doctrine, or if the mandate opens the door to other religious texts.

According to KOCO’s report, Walters told educators: “We’re going to be very explicit that that means teaching stories from the Bible in the grade level, that means teaching its influence on American history. It will all be in historical context. It is academic malpractice not to be teaching the Bible’s influence on American history.”