The word stranger
(alien
in the NIV) refers to permanent residents who served the Lord but could not trace their lineage back to Jacob, Isaac, or Abraham.1 Someone like Rahab would be a stranger since she was a convert from Jericho (see Joshua 2:1–24, Joshua 6:22–25). The mention of strangers confirms the biblical vision and expectation that people from outside of Israel would want to come and worship the Lord.2
9 These were the cities designated for all the people of Israel and for the stranger sojourning among them, that anyone who killed a person without intent could flee there, so that he might not die by the hand of the avenger of blood, till he stood before the congregation.