The Muslim call to prayer normally takes place in a mosque, but later this month American Muslims will gather in a Christian church for the first time.
Pasadena's All Saints Church is hosting the annual Muslim Public Affairs Council (MPAC) Convention.
"As people of faith, we are called to refuse to be polarized around our differences, and to choose instead to be mobilized around those values we share," said Reverend Susan Russell, All Saints Church.
But sharing values can come with a price. Critics are attacking the plan to host the convention, including in an article in the Institute on Religion and Democracy, which portrays the church as a "patsy" for what it describes as an intolerant Muslim faith.
The church has received dozens of angry emails hostile to the convention and Islam.
"Every time they create that kind of noise, they bring the best out of us and the best out of America," said Dr. Maher Hathout, MPAC senior advisor.
While the emails are disturbing, so far they haven't included any direct threats against the convention. Still, security is expected to be heightened.
"We are in contact with the Department of Homeland Security, the FBI, the local police, the sheriff, so we're taking all precautions," said MPAC President Salam al-Marayati.
Everyone is hoping that is all they need to do. But as more people hear about the plan to host a Muslim convention in a Christian church, religious leaders here are bracing themselves for the potential for more controversy.