Honesty is the best policy

This everyday expression means that if a person tells lies he will eventually be found out.
The expression comes from one of Aesop’s Fables, ‘Mercury and the Woodsman’. Aesop lived between c. 620-560 BCE.

An honest Woodcutter working beside a river, dropped his axe by mistake into the river. He sat down and wept, as he had now lost his livelihood.
The God Mercury (Hermes) saw this and took pity on the woodcutter. He dived in and emerged with a golden axe, asking him if it was his. No, replied the woodcutter. So Mercury dived in again and brought up a silver axe, asking him if this was his. No, replied the woodcutter. Finally, Mercury brought up the woodcutter’s own axe, whereupon the woodcutter said yes, the axe was his.
The woodcutter’s honesty so impressed Mercury, that he allowed him to keep all three axes.
Upon hearing this story, a dishonest neighbour threw his own axe into the river and waited for Mercury. Eventually, the God appeared with a golden axe, and asked the woodcutter if it was his. Yes, said the woodcutter. However, on this occasion Mercury not only denied him the golden axe, but refused to give him his original axe.