This story is about a recently deceased man, who finds himself walking along a dark plain towards soothing glowing in the distance. He is accompanied by a hooded figure. There are doors. He is made to believe that he can change his fate if he can identify, relive, and correct the one critical moment in his life. This works, and he is saved. The dark figure takes hope from a rare success, and returns to his critical moment. He is receiving pieces of silver, and is revealed to be Judas.
I would have read this in the late 60's, but I was reading a lot of older stuff at the time, so it could be from the 50's. It was part of a collection of short stories, either a magazine or anthology.