The ass the fox and the lion 驴、狐狸和狮子

An ass and a fox went into partnership and sallied out to forage for food together. They hadn't gone far before they saw a lion coming their way, at which they were both dreadfully frightened. But the fox thought he saw a way of saving his own skin, and went boldly up to the lion and whispered in his ear, "I'll manage that you shall get hold of the ass without the trouble of stalking him, if you'll promise to let me go free." The lion agreed to this, and the fox then rejoined his companion and contrived before long to lead him by a hidden pit, which some hunter had dug as a trap for wild animals, and into which he fell. When the lion saw that the ass was safely caught and couldn't get away, it was to the fox that he first turned his attention, and he soon finished him off, and then at his leisure proceeded to feast upon the ass.

Betray a friend, and you'll often find you have ruined yourself.

驴和狐狸商量好一起去觅食。还没走出多远，突然看见一只狮子走过来，他们俩都吓得不得了。然而，狐狸却想出一条妙计，可以保全自己的性命。他立即跑到狮子面前，附耳小声地说：“如果你答应放我走，我就能保证让你毫不费力地抓住那头驴。”狮子应允了他的提议，狐狸便引诱驴掉进了一个陷阱里，这是某些猎人为捕获野生动物而事先挖掘出的洞。狮子见驴已被俘，再也逃不掉了，于是便转向刚才和他说话的那只狐狸，很快便抓住狐狸吃掉了。然后再慢慢地享受陷阱里的驴。

背叛朋友，你也不会有好下场。