Charles Ellicott Commentary Exodus 22:21

"And a sojourner shalt thou not wrong, neither shalt thou oppress him: for ye were sojourners in the land of Egypt." — Exodus 22:21 (ASV)

For you were strangers. —You should, therefore, sympathize with “strangers;” not vex them, not oppress them, but love them as yourselves (Leviticus 19:34). The condition of foreigners in Israel is shown to have been more than tolerable by the examples of the Kenites (Judges 1:16; Judges 4:11); of Araunah the Jebusite (2 Samuel 24:18–24); of Uriah the Hittite (2 Samuel 23:39), Zelek the Ammonite (2 Samuel 23:37), and others.