Jennings, 43, was killed Saturday night on Burleson Retta Road in a multi-vehicle and pedestrian accident.
"Pray for the family of Brian Jennings," read a Sunday post from the Alsbury Baptist Church Facebook page. Members of the church and community have poured into the Facebook post to leave positive comments.
A memorial service for Jennings will be held at 3 p.m. Wednesday at Venue 510 in Burleson.
Jennings, known as BJ by friends and family, had worked as Alsbury's teens' pastor since Nov. 2006, according to the church website. He and his wife, who had been married since 1993, have three children. The website described Jennings as a fun-loving, serious Mavericks fan.
According to Terry Grisham of the Tarrant County Sheriff's Office, Jennings had stopped on the side of the road to check on a stranded SUV when he was struck by another vehicle.
"Obviously lots of people are grieving," said Alsbury Baptist Church pastor Scott Sharman Monday morning. "BJ's impact was far greater than he would have ever understood.
"I've never had so many emails, Facebook comments, text messages or anything else."
Read one Facebook comment: "Amazingly, brother Jennings served til his last breath.
A total of four people were pronounced dead at the scene, said Matt Zavadsky with MedStar. Nine other people were injured and transported to Fort Worth hospitals.
"At the time that we transported them, two were [in] critical [condition]," he said.
Jennings was among the four people who were killed during the accident Saturday night on the 1500 block of Burleson-Retta Road, a narrow two-lane street that has no street lighting, when they were hit by a red pickup truck.
Alcohol is believed to have been a factor in the accident, Grisham said.
Police were dispatched at 11:59 p.m.
According to the sheriff's office, also killed were 24-year-old Breanna Mitchell of Lillian, who is believed to be the driver of the SUV; 42-year-old Hollie Boyles; and 21-year-old Shelby Boyles.
Jennings was returning to the church Saturday night to drop chairs and tables he had used at his son's graduation party, Sharman said.
Sharman said he had a couple of young children who are members of the church in the car with him. They were transported to Cook Children's hospital as a precautionary measure but are OK, he said.
Burleson City Council took time Monday night to remember Jennings.
"There's an entire church community there that is suffering greatly," Mayor Ken Shetter said. "Keep those people in your prayers."
According to information confirmed by Grisham Tuesday morning, the Boyles, including Eric Boyles, the father of Shelby, had come out from their home to also check on the SUV after Mitchell sought their help.
At some point, Eric went back into the home and Jennings stopped and parked in front of the SUV.
An investigation is still ongoing and details are inconclusive, said Grisham, but based on observations so far, the red pickup truck was the only vehicle in motion when it hit both the SUV and Jennings' pickup truck.
Sixteen-year-old Ethan Couch, first incorrectly described as 17, who was driving the red pickup, also hit an oncoming red Volkswagon carrying 18-year-old driver Ashlyn Evans and 14-year-old Peyton Alan, both of Burleson.
As of Tuesday morning, the sheriff's office had identified that a total of eight teenagers ranging from ages 15 to 19, including Couch, who were riding in the red pickup.
"We had heard from the very beginning that a number of occupants had some connection with the Keller school district," Grisham said. "I spoke with a Keller school official [director of communications Shellie Johnson] and she identified five individuals in the red pickup were enrolled in Keller schools."
The two teens riding in the bed of the truck were the most seriously injured, he said.