Three Hundred Æsop's Fables/The Farmer and the Snake
THE FARMER AND THE SNAKE.
A Farmer found in the winter time a Snake stiff and frozen with cold. He had compassion on it, and taking it up placed it in his bosom. The Snake on being thawed by the warmth quickly revived, when, resuming its natural instincts, he bit his benefactor, inflicting on him a mortal wound. The Farmer said with his latest breath, "I am rightly served for pitying a scoundrel!"
The greatest benefits will not bind the ungrateful.