这是一个非常有名的寓言故事。农夫知道蛇是要咬人的，但是看见蛇冻僵了就可怜起它来，以为只要救了它，它就不会伤害自己了，但他忘了蛇是不会改变本性的。有一种像蛇一样专门害人的恶人，他们也是不会改变害人本性的，不管他们伪装成什么样，千万不能怜惜他们。

This is a very famous fable. The farmer knew that the snake was going to bite, but when he saw that the snake was frozen, he felt sorry for it, thinking that as long as it was saved, it would not hurt him, but he forgot that the snake would not change its nature. There are wicked people like snakes who will not change their nature of harming people. No matter what they pretend to be, you must not pity them.