Saint Thomas

The Gospel According to Thomas is a well preserved early Christian, non-canonical sayings-gospel. It was discovered near Nag Hammadi, Egypt, in December 1945, in one of a group of books known as the Nag Hammadi library.
The Gospel of Thomas (as it is usually known) was found among a collection of fifty-two writings that included, in addition to an excerpt from Plato’s Republic, gospels claiming to have been written by Jesus’ disciple Philip. The Coptic text is composed of 114 sayings attributed to Jesus. The introduction states: “These are the hidden words that the living Jesus spoke and Didymos Judas Thomas wrote them down.”

If you do not know yourselves, then you are in poverty and you are poverty.

Further Reading:
Plato on Know Thyself
Bernard of Clairvaux on Know Thyself
Beryl Pogson on Know Thyself