To whom was the epistle to the James written?
Like Romans, James is quite up-front about who he is writing to:
James, a servant of God and of the Lord Jesus Christ,Of course, "the twelve tribes in the Dispersion" is not exactly a phrase you hear every-day in 21st Century America. So, let's take each piece by itself.
To the twelve tribes in the Dispersion:
First, the "twelve tribes". This is a common way for Jews of Jesus's time to talk about the descendants of Jacob. Jacob had twelve sons whose descendants became 12 tribes who eventually conquered the whole land of Israel. Genesis 49 does a good job of listing the 12 sons (although for complicated reasons, the 12 sons and 12 tribes don't always exactly match up). The "twelve tribes" is shorthand for "all of the Jewish people."
Second, "the Dispersion". In other translations, it says "the Diaspora" which you may have heard in history class. Both words mean "the scattering". Originally, all of the Jews on Earth were located in Israel. Then came God's judgement in the form of Assyrian, Babylonian, and eventually Roman Empires. Babylon, especially, had a policy of splitting up conquered peoples to different places to keep them from organizing into resistance. So, by the time of Rome, the Jewish people were scattered - or dispersed - throughout Africa, Asia, and Europe.
So, "the twelve tribes in the Dispersion" roughly means "all of the Jewish people in all of the world." And, from the context of the letter, we know he was talking to Jewish Christians, in the hope that one day all Jews would embrace Christ.