BOCA RATON, Florida — On the evening of March 14, Hassan Shibly was taking a well-deserved break with his friends and colleagues after a long day of fundraising on behalf of CAIR Florida, an organization focused on improving the understanding of Islam and protecting civil rights, when he received a link to a video.

The video, allegedly filmed by Brenton Harrison Tarrant, was from a helmet-mounted camera, and the perspective was similar to first-person shooter video games. Hassan watched as dozens of Muslims were mowed down in a mosque thousands of miles away in Christchurch, New Zealand, with the hands and gun of the shooter in the foreground, as if this was a game he was playing.

After a minute of carnage, Hassan had seen enough. He jumped into action, posting statements to Facebook and Instagram in order to provide a counter-narrative to the killer’s hateful screed that was circulating online.

His message: that fellow Muslims should not let these events make them feel ashamed about their faith. He’d seen how many Muslims, after events like this, tend to hide their beliefs out of fear. But Hassan believes it’s important for Muslims to be proud of their religion and heritage, especially in times of tragedy. Alongside that message was another: that every mosque should develop a security plan, and central to that plan would be a small team packing firearms.

Hassan wears a gun on him practically all the time. He started carrying one during the 2016 presidential campaign. Back then, Donald Trump’s speeches denigrating Muslims, painting every Muslim as a potential threat, acted as a kind of dog whistle to racists. Soon, Hassan was hearing stories in his community of Muslim women getting harassed in parking lots.

Then the firebombs started. Mosques set on fire in the middle of the night. Then the death threats. At his office in Tampa, the answering machine was filling up with hateful invective. Each incident on its own didn’t frighten him, but seeing the collective pattern emerging was unsettling. He applied for his concealed carry license, and within a few weeks he was carrying a Sig 380. His worst nightmare was an active shooter walking into his mosque while he was giving the Friday sermon.

Now his worst fears had been realized. After the tragedy in Christchurch, Hassan was at the center of a hive of activity, mobilizing a nationwide effort to beef up security at all of America’s mosques. The events at Christchurch have motivated him to redouble his efforts to insure the safety of his community, and to arm more Muslims.