MINCO, Oklahoma - Districts across Oklahoma received a warning letter this week, threatening to sue if Steve Green's "Museum of the Bible Curriculum" was taught in their schools.

The threat comes from a Wisconsin based group whose purpose is to educate the public on the separation of church and state.

This curriculum caught national attention last year following the Mustang school board's approval to teach a bible-based elective course.

But the group called "Freedom from Religion", calls it a violation of the first amendment and said it'll fight any district who teaches it.

The group stated their goal is to protect the separation of church and state. And to continue their quest for this separation a four-page letter was mailed to schools across Oklahoma threatening legal action if the course is taught.

Minco Public Schools Superintendent Kevin Sims said the organization is going too far.

“An organization such as this really has no place telling a public school district in Oklahoma what to teach and what not to teach,” said Sims.

Sims said that decision is up to the school board.

The letter claimed Hobby Lobby's CEO Steve Green's curriculum, "did not teach about the bible, but preached from the bible". And it continued on by saying, "[Green] has developed a bible curriculum that crosses the line"

Currently, Minco does not teach this curriculum or any bible based curriculum, though there's been talk of offering one as an elective.

“I don't believe it's the job of the school district proselytize the gospel of Jesus Christ, that's my responsibility as a father, that's our responsibility in church. But at the same time I don't think it's the place of an institution like this or a group like this to say you can't teach this because it offends us,” said Minco superintendent.

Sims plans to fight the group if the district ever plans to teach this curriculum.

Mustang Public Schools currently does not teach this curriculum saying they've yet to see the final product.