"bar"--spiritual connotation & meaning

In Tom Lehrer’s song “We Will All Go Toigether When We Go,” the second verse starts:
Oh, we will all char together when we char,
And let there be no moaning of the bar.

And in an episode of *The Beverly Hillbillies, Granny is singing a hymn “Back in the corner where you are,” and one line ends with the word “bar.”
What does the word mean as Lehrer and Granny used it?