John Gill Commentary Leviticus 19:33

"And if a stranger sojourn with thee in your land, ye shall not do him wrong." — Leviticus 19:33 (ASV)

And if a stranger sojourn with you in your land

Ben Gersom, and others, understand this of a proselyte of righteousness, who was circumcised, and in all things conformed to the Jewish religion. But it may be interpreted of a proselyte of the gate, who was not an idolater, since he is described as one sojourning with them, and indeed of any stranger, who for a time was providentially cast among them.

you shall not vex him

with hard and grievous words, upbraiding him with his former ignorance and idolatry, and saying to him, as Jarchi observes, yesterday you were a worshipper of idols, and now you come to learn the law; nor distress him by any means in business, or with law suits; (See Gill on Exodus 22:21).