"An eye for an eye, a tooth for a tooth" originated in the Code of Hammurabi around 1772 BC.

Edit: It also appears in the Bible: "You have heard that it was said, 'Eye for eye, and tooth for tooth.'" (NIV, Matthew 5:38) The Gospel of Matthew was estimated to have been written c. 80-90.

I would imagine that some of the oldest sayings in common use probably come from Greek, Roman and Biblical writers.

Examples off the top of my head would be Roman historical quotations such as Julius Caesar's "I came, I saw, I conquered" as recorded by Suetonius.

Or sayings related to stories such as Aesop's Fables such as 'The Tortoise and the Hare'.

There are also a lot of sayings still in fairly common usage which have biblical roots. For example referring to someone as a 'Jonah' or a 'Judas'.

To be honest my answer really only applies to English speaking society and I also realise that I have only really mentioned sayings and no jokes.

There's this thread on the world's oldest jokes Apparently, the oldest recorded joke is a fart joke, which shows some topis for humor have remained the same.

Related question: Have these sayings been consistently used over history, or something that has resurged recently?