AUGUSTA COUNTY, Va. -- After a teacher at a Virginia school handed out a standard homework assignment on Islam, such an angry backlash flooded in that it prompted officials to close every single school in the county as a safety precaution.

"While there has been no specific threat of harm to students, schools and school offices will be closed Friday, December 18, 2015," Augusta County Schools said. Extracurricular activities were shut down Thursday afternoon.

And social media exploded over the school lesson -- a simple drawing assignment -- into a caustic discussion about religion and education.

Draw this

When the world geography class at Riverheads High School in Staunton rolled around to the subject of major world religions, homework on Islam asked students to copy religious calligraphy.

It read:

"Here is the shahada, the Islamic statement of faith, written in Arabic. In the space below, try copying it by hand. This should give you an idea of the artistic complexity of calligraphy."

The illustrative classical Arabic phrase was the basic statement in Islam. It translated to: "There is no god but Allah, and Mohammed is the messenger of Allah."

Angry calls

When students took it home, it was like a spark hitting a powder keg. Some of their parents saw the homework as an attempt to convert their children to Islam.

Calls and emails flooded the school. Some of them demanded the teacher be fired for assigning it.

Cheryl LaPorte had not designed the assignment herself, but took it from a standard workbook on world religions, local newspaper The News Leader reported.

No more shahada

The county school system reacted.

It removed the shahada from world religion instruction. "A different, non-religious sample of Arabic calligraphy will be used in the future," it said.

And it issued a statement saying no one was trying to convert anyone to any religion.

"Neither of these lessons, nor any other lessons in the world geography course, are an attempt at indoctrination to Islam or any other religion or a request for students to renounce their own faith or profess any belief," Augusta County schools official Eric Bond said in a statement to CNN affiliate WHSV.

Not enough

But that hasn't been enough for Kimberly Herndon, who kept her ninth-grade son home from school.

"There was no trying about it. The sheet she gave out was pure doctrine in its origin," she told WHSV.

"I will not have my children sit under a woman who indoctrinates them with the Islam religion when I am a Christian," she said.

By Tuesday, like-minded parents and residents of the town of nearly 24,000 gathered in the sanctuary of Good Will Ministries to voice their grievances, including against the teacher.

The anger may have had an effect. LaPorte told The News Leader that now her job involves getting students through Standards of Learning tests.

At the same time, former students have taken to Facebook to defend her.

"I'm against anyone getting steamrolled by convoluted logic and I'm very pleased to see that there is so many people around me that feel the same way," a supporter wrote.

Security scramble

Back at the school, the sheriff and administrators had begun worrying about security.

On Monday, Augusta County issued a letter reassuring parents that schools in the county were safe. It did not reference the homework assignment but did say that parents had become worried about security.

"All doors are locked with the exception of one front door....Faculty and staff monitor all activities inside and out of the buildings." Standard security procedures, the letter explained.

But as the week went on, officials got more specific about the source of concern -- calls and email messages -- and their target -- the world geography class.

"The school division began receiving voluminous phone calls and electronic mail locally and from outside the area," the school system said. And the "tone and content" were nasty.

The sheriff deployed more officers to county schools and began monitoring the communications. Then all the schools in the county shut down.

Facebook arguments

The homework assignment in Staunton had ballooned into a national argument that was trending on Facebook.

Both sides dished out hard -- those who see the assignment as an affront to their religious beliefs and those who see it as a mind-broadening education assignment.

"This is so WRONG! There is only ONE GOD and HIS NAME is JESUS!" one user posted.

"You THINK ignorance is a GOOD thing!! Heaven forbid we should learn about other cultures when .03% of them are terrorists - while more than 99% are good, honest, moral people," posted another.

As passions overflow, for fear of their potential effects, Augusta County Schools will remain shuttered over the weekend for all activities.