Organizers of the protest dubbed it a freedom of speech event, which included a Prophet Muhammad cartoon contest. Several of the protesters in attendance wore anti-Islam clothing and were seen exercising their second amendment rights.
Numerous Phoenix Police officers stood in a line between the protesters and a group of counter-protesters who arrived as the event began.
The Council on American-Islamic Relations has a response to the protest. "Teaching people hate, and teaching people ways to kill people and throw pig blood or whatever it is these days, it's just really sad to see that," said Yasir Shareef, with CAIR.
Local Islamic leaders are urging valley Muslims not to go to the event.
Ahead of the rally, city of Phoenix workers installed surveillance video camera on light poles outside of the mosque.
Phoenix police and the FBI gathered intelligence and monitored social media, but they say they were more concerned about people who are staying under the radar than they are about organizers and worshippers.
This is the same mosque that Elton Simpson and Nadir Soofi attended. They were shot and killed during their attack at a Prophet Muhammed cartoon drawing contest.
Friday's rally is in response to that terrorist incident in Texas, but it's not just worshippers who are on edge. Neighbors are also nervous about what may happen.
"I mean it's pretty scary because it's putting my kids in danger. It's just a religion. Everybody is allowed to practice whatever religion they like. I'm just guessing I'm going to take off with my kids during the time they come," said Adriana Viguiero, a neighbor.
Friday is Jummah, the Muslim day of communal prayer.
This is mosque also is one of two in the valley that have received threatening letters in the mail. The FBI is still investigating.