A Stag asked to borrow wheat from a Sheep and said he would leave a Wolf as a bond. The Sheep, understandably, did not think much of this offer.
Two wrongs do not make a right.
Aesop For Children
One day a Stag came to a Sheep and asked her to lend him a measure of wheat. The Sheep knew him for a very swift runner, who could easily take himself out of reach, were he so inclined. So she asked him if he knew someone who would answer for him.
“Yes, yes,” answered the Stag confidently, “the Wolf has promised to be my surety.”
“The Wolf!” exclaimed the Sheep indignantly. “Do you think I would trust you on such security? I know the Wolf! He takes what he wants and runs off with it without paying. As for you, you can use your legs so well that I should have little chance of collecting the debt if I had to catch you for it!”
Moral
Two blacks do not make a white.
Townsend version
A stag asked a Sheep to lend him a measure of wheat, and said that the Wolf would be his surety. The Sheep, fearing some fraud was intended, excused herself, saying, “The Wolf is accustomed to seize what he wants and to run off; and you, too, can quickly outstrip me in your rapid flight. How then shall I be able to find you, when the day of payment comes?’
Moral
Two blacks do not make one white.
Ovis, Cervus, et Lupus
Cervus modium tritici ovem rogabat, lupo sponsore. At illa, dolum praemetuens, “Lupus semper adsuevit rapere atque abire; tu de conspectu fugere veloci impetu. Ubi vos requiram, cum dies advenerit?”
Perry #477