An ox and a dog served the same farmer. One day, the dog said arrogantly: "How grand I am! In the daytime, I watch over the cattle in the meadows; at night, I guard the house. But you…"
"Me? What about me?" asked the ox.
"You can only plough or pull a cart," the dog said dismissively.
"Yes, that's true," replied the ox. "But if I don't plough the fields, what is there for you to guard?"