Maybe it was the holiday spirit. Maybe it was because it was the right thing to do.

Or maybe it was a little bit of both that inspired Brian Christopher to perform a simple act of kindness.

The 49-year-old Navy veteran was walking near City Hall Monday when something on the ground caught his eye. It looked like a comic book. Christopher, an amateur artist, picked it up.

It was a wallet with $172 in it. But no credit cards, license, or any other identification.

What would you do? While you are thinking about that, consider this: Christopher is homeless. He has no income. He has three children, ages 14, 12, and 10, in Maryland. He really, really could have used the cash.

Instead, he brought the wallet to the closest police station, where an officer found a receipt inside with a name and telephone number. The police officer used that to track down the owner, who picked up the wallet. All the money was there.

Yesterday, Christopher admitted he had struggled with the temptation to keep the cash.

“I counted the money and said, ‘Wow, I could probably get three nice presents with this,’ ’’ he said at the Frog Pond in Boston Common, where he had gone to skate. “But maybe it was some student’s Christmas gift money. I just kept thinking of the meaning of Christmas.’’

It turns out the owner, Meghan Schultz of Cambridge, really needed the money, too. The bike messenger put the wallet in her back pocket. It slipped out as she was making the rounds.

“I had pretty much written it off,’’ said Schultz, 22. “For me that’s a pile of cash.’’

To her surprise, she got a call from Officer Richard Osberg of District One. When she came in to claim her wallet, she also got Christopher’s phone number.

“I wanted to see if I could take him out to lunch,’’ she said. “It’s not like I have a ton of spending money but I can afford this.’’

Christopher served in the Navy in the 1980s in a noncombat position before receiving an honorable discharge. He worked for a while as a bartender at Cheeseburger in Paradise in California, Md. Christopher, a native of Quincy, returned to Massachusetts this month. But his parents did not have room to take him into their Braintree home. And because his mother spends her time looking after his father, a veteran who is disabled after a stroke 10 years ago, they could not help out their son. (His wife lives with their children in Maryland.)

Last week, after failing to find a job or a place to live, Christopher checked into the New England Center for Homeless Veterans on Court Street.

He was outside the building when he saw the wallet. “I was facing a conundrum, a real moral dilemma,’’ Christopher said.

Christopher called a friend in Las Vegas and asked her advice. He called his case manager at the shelter, Reneé MacLean. They both suggested that he turn the wallet in to police.

“Doing the right thing when no one is looking shows something wonderful about his character,’’ MacLean said. “It’s definitely nice, especially around Christmas.’’

Osberg, the police officer, said that people occasionally turn in property that they find on the street, and not only the ones who can afford to.

“It’s always good when people make the right decision when they come across anything of value,’’ Osberg said. “Just because someone’s homeless doesn’t mean he doesn’t have a moral compass.’’

David Filipov can be reached at filipov@globe.com., L. Finch can be reached at lfinch@globe.com.

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