Cleobis and Biton
Source: retold by Robert Graves in The Greek Myths.
Cleobis and Biton, two young Argives, were the sons of Hera’s priestess at Argos. When the time came for her to perform the rites of the goddess, and the white oxen which were to draw her sacred chariot had not yet arrived from the pasture, Cleobis and Biton, harnessing themselves to the chariot, dragged it to the temple, a distance of nearly five miles. Pleased with their filial devotion, the priestess prayed that the goddess would grant them the best gift she could bestow on mortals; and when she had performed her rites, they went to sleep in the temple, never to wake again.