Dallas Police Chief David Brown is grateful for his Christian faith and God's "sweet, tender mercy," especially after a gunman killed five police officers during a Black Lives Matter protest last July 7.

Brown told the Chicago Tribune that it was God who gave him the strength to face a "beyond challenging" situation such as the death of his men.

"I'm running on fumes...It's going to be the most challenging thing in my life," Brown said. "I don't know how I'm going to do the rest of the week."

But "I'm a person of faith," he continued. "I believe that I'm able to stand here is a testament to God's grace and his sweet tender mercies, just to be quite honest with you. This tragedy... will not discourage us from changing and performing policing in America."

Brown was talking about the murderous rampage of 25-year-old Micah Johnson who used a sniper's rifle to open fire on police officers accompanying people who were protesting the deaths of Alton Sterling and Philando Castile, both black men who were killed by police officers.

Brown is heartbroken over the loss of his men but is amazed at how valiantly they acted amid terrifying circumstances.

"They're brave. They're courageous. They did things that day that are just hard to describe. We're learning that officers exposed themselves to draw fire, so they could determine what floor this suspect was on, exposed themselves," Brown said during an interview with CNN's "State of the Union with Jake Tapper."

"And you saw footage of officers running toward gunfire, extraordinary acts of bravery, countless officers returning fire, knowing that they're vulnerable to try to get to wounded and injured citizens and officers to get them rushed to the hospital to try to save their lives, and just the brave men and women who have worked every day," he added.