The world isn’t meant to become one people. It’s meant to turn to one God.

God’s first word to Abraham already reaches past Abraham: through him “all the families of the earth” are to be blessed — and they stay families, plural, distinct. The Hebrew nivrechu can be heard, beyond “be blessed,” as a word of grafting — one branch bound into another. On that reading Israel is not sent to replace the peoples of the earth but to connect them; the blessing runs through Israel to a world that remains many.

Isaiah’s nations are not conquered and not converted: they climb to Zion of their own accord, and what they come for is to learn — “that He may teach us of His ways.” They take instruction in the knowledge of God and His justice, then walk home along their own paths, still themselves. The next verse completes the picture: they beat their swords into plowshares and learn war no more. Unity here is not sameness; it is a world that has stopped fighting because it has turned to one God.

Here Israel’s own role is named: not ruler of the nations, but “a light to the nations” — and a “covenant-people,” a people that is itself a covenant held out to others. A light is not a net; it illuminates without capturing. This is the phrase the world later shortened to “a light unto the nations,” and its sense is service, not dominion: to carry something the nations can see by, and come toward on their own.

Rabbi Yehuda Halevi — writing in twelfth-century Spain, his Kuzari composed in Judeo-Arabic and read ever since in Ibn Tibbon’s Hebrew — gave the relationship its sharpest image: Israel among the nations is like the heart among the limbs. The heart is the most sensitive organ, the first to feel the body’s sickness — but its whole life is to keep alive a body that is not itself. A people set apart, in this picture, is not set above; it is set to serve.