This is a joke told on the Gaither Homecoming (southern gospel) program.

The wealthy atheist bachelor and poor Christian widow were neighbors. He would pick on her for her “superstition” and she would pray for his “poor lost soul.” Times got hard and she ran out of money and food. He offered to buy her groceries but she stubbornly refused because “…her God would not leave her to accept charity from an atheist.” Time passed he finally felt so sorry for her that he bought and left a load of groceries on her porch. Next day she came over and bragged.
She: “I told you my God would supply my needs.”
He: “I’ve got you now! It wasn’t your God, but your atheistic neighbor, who brought you the groceries.”
She: “It’s just like an atheist to try to take the credit! I tell you, it was God’s work! And to show how great he really is, he forced the devil to make the delivery!”