Israel's Priestly Purpose for All Nations

Israel was made a kingdom of priests, and a priest exists for somebody else. Isaiah says it directly: a light to the nations.
That is the point most often missed. Israel's status as Yahweh's own portion was not an end in itself, but the means by which Israel would draw all the nations back to Yahweh. Being chosen was a job, not a privilege held against others.
And Revelation closes the loop with the same vocabulary. Those ransomed from every tribe and tongue are made a kingdom and priests, and they will reign on the earth - said in a divine council scene, in connection with ruling over all the earth.
Scripture links:
- Isaiah 42:6 - a light for the nations.
- Revelation 5:10 - you have made them a kingdom and priests to our God.
The election was never the end of the story. It was the mechanism of it.