The Viper and the File
A Viper, crawling into a smith's shop to seek for something to eat, cast her eyes upon a File, and darting upon it in a moment, "Now I have you," said she, "and so you may help yourself how you can; but you may take my word for it that I shall make a fine meal of you before I think of parting with you." "Silly wretch!" said the File, as gruff as could be, "you had much better be quiet, and let me alone; for, if you gnaw for ever, you will get nothing but your trouble for your pains. Make a meal of me, indeed! why, I myself can bite the hardest iron in the shop; and if you go on with your foolish nibbling I shall tear all the teeth out of your spiteful head before you know where you are."
Take care that you never strive with those who are too strong for you, nor do spiteful things, lest you suffer for it.