They came together before a statue of the Blessed Mother yesterday to sip coffee, nibble cake and reflect on the miracle they managed to pull off.

Much like David with his slingshot, this band of South Boston neighbors managed to stop the condo Goliath in its tracks. It wasn’t easy. And it wasn’t cheap. But they did it.

This plucky group from Old Harbor Street managed to upset the prevailing law of gravity in Southie right now that says anything not nailed down will be converted to condos.

That’s precisely what was supposed to happen to a sliver of open space on Old Harbor Street, owned by the ­Marian Manor Nursing Home, and known for more than half a century as “Mary’s Garden.”

The plan was to shoehorn as many as nine condos into the plot. Back in June, there seemed to be an air of inevitability about the proposed deal that South Boston developer John Cronin entered into with the Carmelite Sisters, who operate Marian Manor. They had approached him about selling off Mary’s Garden to help lift their sagging finances. Cronin held the purchase and sale on the property.

At that June meeting, Kristin Ventresca, who lives on Old Harbor Street and whose grandmother was cared for at the Manor, asked the question no one was willing to answer.

Why didn’t the nuns at Marian Manor let the neighbors know about their plans to sell Mary’s Garden?

“When I asked, I thought it was probably too late,” Ventresca said yesterday, “but I thought if given a chance, there were enough neighbors on the street who’d be willing to pull together a plan of our own.”

The neighbors’ plan was both simple and ingenious: They would counter the developer’s offer of more than $900,000 to build condos on Mary’s Garden by offering something just as valuable in Southie these days … a deeded parking space.

“It’s easy to be against something,” said Rudy Ventresca, Kristin’s husband, “but we knew that wasn’t going to be enough to prevent a condo village from being built here. If we didn’t want all the extra congestion and the extra cars, then we had to come up with both a plan and the money to back it.”

And they did. Mary’s Garden will eventually be reconfigured into a garden of 18 parking spaces that have already sold for $70,000 each.

Christine Elmore does not own a car. Yet, she has purchased a space in the garden because her home stands 18 inches from where the proposed condos in Mary’s Garden were supposed to rise.

“For me, it was both an investment and insurance,” Elmore said.

In fairness, the city deserves a shout out here. The mayor’s office tapped Dan Manning, a Southie resident and the city’s chief of staff for civic engagement, to help broker discussions between Cronin and the Old Harbor Street neighbors.

In the end, everybody won. The Carmelite Sisters got the money they needed, Cronin agreed to place community ahead of cash and condos, and a group of neighbors managed to take control of their own destiny.

Yesterday, after the coffee was served, workers arrived to hoist Mary’s statue out of the garden where it stood for almost 50 years. It was relocated to a courtyard inside the Manor. Kristin Ventresca said the group will place a duplicate statue of the Blessed Mother in the parking lot when it’s completed in the spring.

Sister Margaret Therese snapped a cellphone picture of Mary as she floated above Old Harbor Street in a sling.

“You see,” she said softly, “Our Lady always provides.”