Mary is the snarky one. Margaret is the sweet one.

The O'Brien sisters, raised Catholic right here in Savannah, have their faith and even their friendship put to the test in Evan Smith's play The Savannah Disputation. When a pretty young proselytizer named Melissa knocks on the door and perkily asks if they want to know all about Jesus, Mary and Margaret have powerfully different reactions.

It's the Deep South, but Melissa's not a Bible-thumping Baptist caricature in Smith's show, which starts a two-weekend local run Jan. 10 at Muse Arts Warehouse.

"I would say she's an evangelical zealot who's not from any particular church you've ever heard of before," laughs actress Carmel Garvin Hearn, who's playing the gullible Margaret.

Directed by Tom Coleman, The Savannah Disputation is the Savannah Community Theatre's first show for 2014. "Smith understands that the strange boundaries separating Christianity and Catholicism may be innocuous to the casual observer," said Time Out New York, "but to those in either camp, they're as distinctive and divisive as race or ethnicity."

Much more than a dry give-and-take between religious ideologies, The Savannah Disputation is a laugh-out loud comedy. "Faith," declared the Boston Globe in its review, "is a complicated business — and even sometimes, a funny business, too."

Hearn considers the play a rich combination of styles. "There are a lot of funny moments in this play — but it's not a complete comedy from beginning to end," she says. "It's sort of a theological episode of The Golden Girls. There are lots of laughs, but then there's moments where you pause and you reflect. The first act is a little lighter, a little more funny, and the second act has some more poignant moments in it.

"I will say that each of the characters, by the end of the show, has had a metamorphosis."

The show is designed to inspire thought and theological debate, Hearn explains, not hammer home some sort of religious agenda. "We don't want this to have that effect on anyone," she says. "We really don't.

"We actually invited a Catholic priest to read the script, come see the show and advise us that we're presenting what we think we're presenting. And he's given us his blessing. He really sees the message."

The fourth character in this religion-go-round is Father Murphy, brought in (by sour, skeptical Mary) as a ringer to argue faith with the zealous Melissa.

Mary is played by veteran Savannah thespian Anna Burrell, who returned to the local stage (after a six-year absence) in a 2013 production of the Greek tragedy Medea. Although she performed in plenty of comedies, Burrell was — for years — considered the finest dramatic actress in the area.

"I focused on other things, really," Burrell says about her time offstage. "And artistically speaking, they weren't terribly satisfying. Medea just sort of happened — a friend asked me to be in it. I was like, I can't believe you're asking me to be in this play. I was very fortunate that that happened. And I was fortunate to run across Tom Coleman, also.

"I think it's always good to work with someone new, and I'd never worked with Tom before. It's a new approach for me. Tom's whole approach towards directing is not what I had been working with for the last 5,000 years. It's great. It's a new way of looking of things."

Burrell says she's looking forward to acting in Savannah again. She's especially glad that JinHi Soucy Rand opened Muse Arts Warehouse — in the old days, Burrell explains, "space was always the problem."

Like Medea, The Savannah Disputation is being staged at Muse. "JinHi has an amazing space," adds Burrell. "And she's the most generous host you can imagine on the planet."