Before the church massacre in Sutherland Springs, Tex., there was the church massacre in Charleston, S.C. It was enough to make the Rev. John Darsey think that his young Georgia church needed a security plan — one that involved defenders with firearms.

So his church, Redeemer Church of Madison, hired three uniformed sheriff’s deputies for each Sunday service, one directing traffic, one in the parking lot, and one right by the door.

This is the visible deterrent — the first line of defense.

The second, more subtle layer is an in-house security team of church members with military or law enforcement backgrounds, all carrying concealed weapons. Inside the spare, spacious modern sanctuary — where some 500 people come every Sunday morning — the team members split the room into quadrants, with one always keeping a bird’s-eye view from the back of the room, on the riser with the sound and lighting equipment.

The third layer of protection is one that Mr. Darsey knows is there, though he has trouble quantifying it. He estimated that about 20 to 25 of his flock were concealing a weapon on any given Sunday. “Now that’s just the ones I know about,” he said.