According to Chicago police and fire investigators, a burning shirt was spotted hanging on the front door of the church's gymnasium and community center at approximately 2:15 a.m. Wednesday.
A charred door handle is the only damage left behind.
Pfleger, the church's pastor, says he believes a gangs are responsible for the act. He also says this is the third time something similar has happened.
"We've had this twice in the last six weeks to eight weeks, where we've had something," said Pfleger told reporters outside the South Side Catholic church. "The other two times, it was bags of feces that were tied -- once to the church door, once to the school door."
"They're kidnapping each other; now, they want to start attacking the house of God," said St. Sabina parishioner Hattie Stokes. "This is our church. This is our Holy Week. We're in preparation for Easter, for the rising of Christ, and it hurts."
On Tuesday, Pfleger denounced gang activity and demanded that the store where a man was killed recently close its doors.
"That store we went to is one of the hangouts of one of the gangs here, the G- Villes, that's their hangout," said Pfleger. "As we said yesterday, we want that store closed. We want all the gang hangouts closed."
Arson investigators are trying to figure out who started the fire. They are looking at surveillance video that shows one suspect walking up to the door and starting the fire.
"I think that a person who attacks a church, but not only any church, one that is very visible, is wanting to be caught and that is going to happen," said 17th Ward Alderman Latasha Thomas.
In the meantime, Pfleger says the vandalism won't stop his message. Other community leaders also say their fight against gangs will remain strong and loud.
"Our message is we're not going to stop," he said. "We're going to continue to say we want the store closed and continue to do what we do until the violence ends."
Until someone is caught, St. Sabina church members will celebrate Holy Week on the look out.
"Our Savior died. So, the burning of a door is little or nothing," Pfleger said.
While Pfleger says the fire is not a big deal, Philip Jackson with the community group Black Star Project says it is a big deal and the city must use the incident to support Pfleger's work against violence.
"There is no question about his value to the city of Chicago, and not just the South Side or the West Side but to the whole city of Chicago, so when things like that happen, the whole city should be outraged," said Jackson.
There are no specific plans to add extra security around the church.
One group is offering a $1,000 reward for any information leading to an arrest.