This was copied from another forum.

A Post Office worker at the main sorting office finds an unstamped, poorly
hand-written envelope addressed to God. He opens it and discovers it is from
an elderly lady, distressed because some thief robbed her of 100 dollars. She
will be cold and hungry for the rest of the month if she doesn't receive some
divine intervention.

The worker organizes a collection amongst the other postal workers, who dig
deep and come up with 96 dollars. They get it to her by special courier the
same morning.

A week later, the same postal worker recognizes the same hand on another
envelope. He opens it and reads: "Dear God, Thank you for the 100 dollars.
This month would have been so bleak otherwise. P.S. It was four dollars short
but that was probably those thieving bastards at the Post Office."

P.S. My father (RIP) worked at the post office for 28 years, and he would have loved this joke.