How long shall I bear with this evil edah, who are complaining against me," exclaims God in exasperation after the episode of the spies (Numbers 14:27). The rabbis understand the word edah as referring here to the group of 10 spies who discouraged the people by testifying falsely to the invincibility of the inhabitants of the land.
Edah is loosely used to mean a "community;" for example, the Edah Charedit is the charedi community, and Edot Hamizrach is the politically correct term for Jews from North Africa and the Middle East who used to be known as Sephardi.
However, etymology gives a more precise definition. Edah is related to the word ed, meaning "witness." Hence an edah is a group or community people that bears witness. By comparing the use of edah in the story of the spies to its use in Leviticus 18, "And I shall be made holy within the edah of Israel," the rabbis learn that 10 is the minimum number for events which publicly sanctify God - the root of the concept of a minyan.
The Jewish people is sometime referred to as Edat Yisrael. The point of our being in the world is to bear witness to God, through our way of life and through our extraordinarily improbable, even miraculous, continued existence.
"‘You are my witnesses,' says God" (Isaiah 43:12). On this, the Midrash comments boldly, "If you are My witnesses, then I am God; if you are not My witnesses I am, as it were, not God."