WASHINGTON—The family that brought reasonably priced scrapbooking materials to American consumers and religious freedom to corporations is now looking to complete its mission by restoring a Washington landmark and turning it into a monument of biblical proportions. The owners of the Hobby Lobby craft store chain plan to convert the Washington Monument from obelisk into a giant Christian cross.

Together with a yet to be named Bible museum two blocks south of the National Mall, the $800 million undertaking is scheduled to open to the public in 2017.

“While we appreciate our Founding Fathers’ contribution in establishing our Christian nation,” said Steve Green, president of the $3 billion company and son of its founder, “it is our Heavenly Father we must recognize for giving us this gift.”

While a national fundraising campaign is in the works, the Green family has provided the initial financing, as well as the marble, granite, and bluestone gneiss that will complete the crucifix.

“God has provided us the raw materials,” said Steve Green, “which, in his infinite wisdom, he conveniently stocked in our Hobby Lobby distribution center.”

Because the Washington structure they wish to redesign is considered a historic landmark, the family’s vision requires final approval from the city’s historic preservation review board, expected by late July.

Their construction plans, submitted to the board, indicate that the Greens plan to “tastefully Bedazzle” portions of the monument.

“Jesus was a craftsmen,” said Green. “And we know crafts—and Jesus. The question is, ‘does the rest of the nation?’ ”

Green worries that “this nation is in danger because of its ignorance of what God has taught.” To save the soul of the country, he and his family are seeking to “bring Americans together under the cross” and reintroduce them to the Bible, a book Green calls “a reliable historical document.”

The Washington location was chosen for its concentration of tourists and national prominence. Green anticipates that millions of people will visit the museum every year to view rare biblical artifacts and visit the gift shop.

The historic preservation officer for the District of Columbia noted, “Sure, the National Mall could use a few more shops. With Hobby Lobby as the anchor store, there’s no reason we couldn’t transform this landscape into the new Mall of America—a real Mecca, if you will.”