Ch 08 On Rules For Conduct In Life - Maxim 61

The noblest of beings is evidently man, and the meanest a dog, but intelligent persons agree that a grateful dog is better than an ungrateful man.

A dog never forgets a morsel received
Though thou throwest a stone at him a hundred times.
But if thou cherishest a base fellow a lifetime,
He will for a trifle suddenly fight with thee.