The Donkey in the Lion's Skin
A Donkey once found a Lion's skin which the hunters had left out in the sun to dry. He put it on and went towards his native village. All fled at his approach, both men and animals, and he was a proud Donkey that day.
In his delight he lifted up his voice and brayed, but then every one knew him, and his owner came up and gave him a sound cudgeling for the fright he had caused.
And shortly afterwards a Fox came up to him and said, "Ah, I knew you by your voice."
Fine clothes may disguise, but silly words will disclose a fool.