Oft quoted is the idea that the Jews are to be “a light unto the nations,” popularly understood to mean that Israel will set an example for all humankind through excellence in behavior.
This idea originates from a verse in Isaiah:
“I am the Lord, I have called you in righteousness, and I will strengthen your hand, and I will form you (alt. “protect you”) and I will give you as the covenant of a people, as a light unto the nations.” (42:6)
(The translation here is my own. I have rendered the Hebrew “or goyim” as “a light unto the nations” following the popular phrase, just to avoid confusion, though otherwise I’d prefer to translate it as: “a light of nations.”)
As usual, the popular understanding of this phrase is challenged by a quick glance at the commentary of Rashi.
“I have called you” — [God] says to Isaiah.
“and I will form you” — ‘When I formed you, this was My thought, that you will return My people to My covenant.’
“as a light unto the nations” — Each tribe by itself is called a nation, as it says (Genesis 34:11, G-d blessing Jacob), “a nation and a congregation of nations shall come forth from you.”
According to Rashi, G-d addresses here not the people of Israel but Isaiah himself, revealing to him his mission to be a light unto “nations,” that is, to the tribes of Israel.
It seems then, that the notion, supposedly based on this verse, that the Jews are charged to act as a light unto the nations (of the world) is greatly overstated. Rather, G-d’s desire, as stated here, is that the Jews’ primary concern be the honoring of its own covenant with G-d. This will be the greatest “enlightenment” our people can strive to achieve.