I'm the local manager of a discount grocery store; we are part of a large chain that operates mostly in lower-income neighborhoods. My store is in an area that has a large Afghani immigrant population, many of whom are Muslims. One of my employees, whose job is to keep shelves stocked and help customers find items, is an evangelical Christian. I've received a number of complaints from customers about his efforts to engage them in discussions of religion and convert others to his religious views. I held a disciplinary meeting with him and explained that he must stop this behavior. He told me that his religious beliefs require him to testify about his faith to everyone that he meets, particularly those who will not be saved unless they repent and convert. He's otherwise a good employee, and I don't want to stifle his beliefs. But he's driving customers away, and we will really suffer if we get a reputation as unfriendly to certain religions. What are the legal requirements here?