The Donkey of Rabbi Pinchas ben Yair
On his way to redeem captives, Rabbi Pinchas ben Yair's donkey refuses untithed barley until the innkeepers separate maaser, teaching that Hashem guards the righteous.
The Gemara in Chullin (7a) records the remarkable journey of Rabbi Pinchas ben Yair as he traveled to redeem captives. Along the way, he arrived at an inn where his donkey was offered barley. Despite being hungry, the donkey refused to eat. The innkeepers sifted and cleaned the barley multiple times, but the animal still stubbornly abstained.
Finally, Rabbi Pinchas suggested that perhaps the barley had not been tithed. The moment the innkeepers separated the ma’aser, the donkey happily began to eat. The Gemara uses this famous incident to establish a sweeping principle: if Hashem does not allow a pitfall to occur through the animals of the righteous, He certainly will not allow the righteous themselves to stumble into sin.