Charles Ellicott Commentary Exodus 23:9

"And a sojourner shalt thou not oppress: for ye know the heart of a sojourner, seeing ye were sojourners in the land of Egypt." — Exodus 23:9 (ASV)

Thou shalt not oppress a stranger. —See Note on Exodus 22:21. The repetition of the law indicates the strong inclination of the Hebrew people to ill-use strangers, and the anxiety of the legislator to check their inclination.