What is the meaning of the text inside this AMS logo?

[![enter image description here][1]][1]

The image is from [here][2], and the logo seems to have been frequently used until the 80's. The text is

>ΑΓΕΩΜΕ ΤΡΗΤΟΣ ΜΗ ΕΙΣΙΤΩ

but Google translate and Googling have not helped. 


  [1]: https://i.sstatic.net/U82jy.png
  [2]: https://www.ams.org/journals/notices/198603/198603FullIssue.pdf