Before more than 24,000 Jehovah's Witnesses stream through the doors of the Liacouras Center for a series of weekend conventions scheduled to begin Friday, a volunteer crew transformed the site of hundreds of sweaty basketball games into an auditorium suitable for the sacred.

Holding that cleanliness truly is next to godliness, nearly 1,000 Jehovah's Witnesses wiped the Temple University facility clean.

They swept and mopped floors, scraped up dried gum from aisle stairways, and dusted chairs until they shone.

Over 800 Jehovah’s Witnesses, including Cynthia Spencer, 60, Warmister, swarm over the Liacouras Center June 22, 2017 to clean everything in sight, a day before 24,000 members converge on the center for a series of weekend conferences. CLEM MURRAY / Staff Photographer
Clem Murray/Staff photographer
Over 800 Jehovah’s Witnesses, including Cynthia Spencer, 60, Warmister, swarm over the Liacouras Center June 22, 2017 to clean everything in sight, a day before 24,000 members converge on the center for a series of weekend conferences. CLEM MURRAY / Staff Photographer

"We encourage cleanliness, keeping our homes clean, our persons clean, and our places of worship clean," said Roland Cooper of Sewell, an elder and  a spokesman for the region's 45 congregations. "We want to make sure the facility represents the principles we live by, and we represent God."

The ritual, rooted in the belief that Jehovah is a "clean God," is a precursor to the meetings expected to draw the faithful from Pennsylvania, New Jersey, Delaware, and Maryland.  About 6,000 Witnesses will gather for each of four consecutive Friday-to-Sunday sessions through July 16.

This year's  conventions' theme, "Don't Give Up,"  focuses on sustaining belief and practice through challenges, and will be explored in films, lectures, discussions, and music and video presentations. About 30 new followers are to be baptized on Saturday.

The local events are among scores of international three-day gatherings held annually for the religion, which claims 8.3 million worldwide followers. The ranks have swollen by about 250,000 members a year during the last decade, it says, and about 1.25 million Jehovah's Witnesses reside in the United States. Meetings will be held this year in Reading and Trenton. Admission is free, and the gatherings are open to the public.

Jehovah's Witnesses, who are known for canvassing neighborhoods to share their faith, identify as Christians, but tenets of their religion differ from those of other Christian groups. Jehovah's Witnesses believe that Jesus is the son of God but not part of a trinity. They do not believe in hell, or that the soul is immortal. They refuse blood transfusions, citing their interpretation of Scripture.

This year's endurance theme is appropriate given the faith's most recent struggles, said Emily B. Baran, an assistant professor of history at Middle Tennessee State University and author of Dissent on the Margins: How Jehovah's Witnesses Defied Communism and Lived to Preach About It.

In April, Russia's Supreme Court ruled that Jehovah's Witnesses constituted an "extremist" organization. Describing some of its nontraditional beliefs as radical, the court banned the group and ordered it to hand over all property to the state. An appeal is scheduled for July 17.

The ruling has been condemned by human rights activists and organizations including the U.S. Commission on International Religious Freedom.

"What's happening now is what has always been happening [to Jehovah's Witnesses] for the past 100-plus years," Baran said. "In the U.S., it's mostly an annoyance factor of having someone knock on their door at an inconvenient time. In other parts of the world, there is more serious hostility."

Cooper said the choice of the conferences' theme was coincidental and had been made more than a year ago, adding that the Bible  warns of persecution, so Witnesses expect that "our worship may come under attack and our freedom may be challenged."

Baran said the cleaning practice could be viewed as an effort to make a good impression and combat some views that are "not immediately positive."

"They want to demonstrate that they are law-abiding, decent citizens that add value to the community," Baran said.

Cooper said the preparation of the center had a biblical foundation. As a basis for encouraging believers to live physically and spiritually clean lives, the faith points to passages that include Psalm 18:26, "With the pure you show yourself pure," and Leviticus 11:44, " For I am the Lord your God: ye shall therefore sanctify yourselves, and ye shall be holy; for I am holy."

Volunteers will clean the 340,000-square-foot Liacouras Center the day before each of the weekend convention sessions, but Thursday's scrub-down will have been the most extensive.

Asha Clark, a 23-year-old school bus driver from New Castle, Del,, scraped gum from the floor. Cynthia Spencer, a legal secretary from Warminster, wiped down chairs with her 39-year-old daughter, Taryn.

"God is a god of order and cleanliness," said Spencer, 60.   "When we come in for worship, we are in our finest, and we want to sit in a clean place."

Joe Sheridan, general manager of the Liacouras Center, said his staff works hard to make sure the facility stays spic and span, but he appreciates the help.

"How they prepare for their worship is amazing," Sheridan said.

Heidi Howard, also of Warminster, has been participating in convention cleaning since she was 6, when she scrubbed venues alongside her parents.  She has helped clean indoor and outdoor facilities including Veterans Stadium.

"We want the place to look nice for people who come to worship and visit,' said Howard, 51, an insurance claims representative. "It's fun. We have a good time – and it's better than going to work."