The Greatest Gift by Philip Van Doren Stern

The original 1943 short story by Philip Van Doren Stern on which the film "It's a Wonderful Life" was later based.

Full text available online,

https://www.onelimited.org/ss-stern-01

The little town straggling up the hill was bright with colored Christmas lights. But George Pratt did not see them. He was leaning over the railing of the iron bridge, staring down moodily at the black water. The current eddied and swirled like liquid glass, and occasionally a bit of ice, detached from the shore, would go gliding downstream to be swallowed up in the shadows under the bridge.

The water looked paralyzingly cold. George wondered how long a man could stay alive in it. The glassy blackness had a strange, hypnotic effect on him. He leaned still farther over the railing...

“I wouldn’t do that if I were you,” a quiet voice beside him said.

There are fragments of background about the origin of the story on various websites. One or two state that the complete story came to Stern in a dream in 1938.

Stern himself apparently said it came to him complete, while shaving. That doesn't contradict that it was from a dream, both could be true.

from: https://blogs.loc.gov/catbird/2018/12/fr...rful-life/

Stern wrote in his notes (and in the New York Herald Tribune on December 15, 1946) that the idea for this story came to him “complete from start to finish” while he was shaving on the morning of February 12, 1938. He wrote an outline that day and put it away. The story stuck with him, and after a few months he wrote what he called a “pretty terrible” first draft. Stern returned to the story periodically, and after revising it several times finally showed it to his literary agent in April 1943. The agent liked it, but told him that she thought a fantasy story would be hard to sell to magazines.

The least reliable information is on (where else?) wikipedia which asserts without supporting references that the story was either 'loosely based on' or 'reminiscent of' a work by Charles Dickens. Unless there is more evidence I think that is just made up.