Never Ask a Fox for Its Skin

"Long ago, there lived a young man, called Lisheng, who had just married a beautiful woman, but she was spoilt and wilful. One day, she had an idea that a coat of fox fur would look pretty on her. So, she asked her husband to get her one. But a fox coat is rare and too expensive. The helpless husband was ashamed to go home and tell his wife that he couldn’t give her the fox coat she desired, so he took the long way home, over the hills. As luck would have it, a fox walked into view, Lisheng quickly grabbed it by the tail.
‘Get off!’ Said the fox. ‘Let go of my tail!’
'Well, dear fox, I’m not letting you go until you take your skin off and give it to me to make a coat. You don’t mind doing this for me, do you?
"The fox thought that Lisheng was crazy, of course, but one has to be careful when around crazy people, so he replied calmly, 'Well, my dear fellow, that's easy. But let my tail go so that I can pull off my skin for you.' The delighted man let go of the fox’s tail happy to oblige if it meant getting the skin. But the moment the fox got free, he ran away as quickly as he could into the forest - laughing.
And – the moral is.
It is pointless to ask something of someone that they are not able or willing to give.