Delegate your task wisely, and only to people you trust.

A Wolf had been prowling around a flock of Sheep for a long time,
and the Shepherd watched very anxiously to prevent him from
carrying off a Lamb. But the Wolf did not try to do any harm.
Instead he seemed to be helping the Shepherd take care of the
Sheep. At last the Shepherd got so used to seeing the Wolf about
that he forgot how wicked he could be.

One day he even went so far as to leave his flock in the Wolf's care
while he went on an errand. But when he came back and saw how
many of the flock had been killed and carried off, he knew how
foolish to trust a Wolf as he exclaimed. “I have been rightly
served; why did I trust my sheep to a Wolf?”

No disguise will hide one's true character.

An Ass found a Lion's skin left in the forest by a hunter. He
dressed himself in it, and amused himself by hiding in a
thicket and rushing out suddenly at the animals who passed
that way. All took to their heels the moment they saw him.

The Ass was so pleased to see the animals running away from
him, just as if he were King Lion himself, that he could not
keep from expressing his delight by a loud, harsh bray. A
Fox, who ran with the rest, stopped short as soon as he heard
the voice. Approaching the Ass, he said with a laugh:

"If you had kept your mouth shut you might have frightened
me, too. But you gave yourself away with that silly bray."

A fool may deceive by his dress and appearance, but his words
will soon show what he really is.