Millions of Americans rushed to stores all across the United States Nov. 24 to take advantage of Black Friday, the day when most retailers offer promotional sales. Back in Turkey, some major department stores in big cities tried to emulate this foreign tradition, declaring major sales for “Kara Cuma,” as Black Friday translates in Turkish. In return, however, they received an unexpected tsunami of condemnations for insulting Islam. To many Turks, the term sounded like a rude term for Friday, Islam’s holy day.

The storm began with the hashtag #KaraCuma. “Friday is blessed. Black is only the color of those whose hearts are deprived of its sacred light,” wrote one angry Twitter user, condemning the “heretics” who brought the term into use in Turkey. Another declared, “The crusader mentality that calls Islam’s holiest day #BlackFriday is apparently filled with fear. But fear will not save them.” Then he quoted the Quran: “God will perfect his light even if the unbelievers dislike it.”

Thousands of similar messages filled the Turkish social media scene in just a couple of hours. Angry protesters began to share lists of the Turkish companies running Black Friday ad campaigns. These companies were imagined to be involved in an effort to “ban their employees from [Friday] prayers.”

The anger turned physical. In a shopping mall in the central Anatolian town of Bolu, a small group walked into a department store and demanded workers remove the Black Friday posters, telling them to do so “if you are a Muslim.” The video of the scene was posted online and went viral.