וְגֵ֥ר לֹא־תוֹנֶ֖ה וְלֹ֣א תִלְחָצֶ֑נּוּ כִּֽי־גֵרִ֥ים הֱיִיתֶ֖ם בְּאֶ֥רֶץ מִצְרָֽיִם׃
И не будь чужаком, не притесняй его; ибо вы были странниками в земле Египетской.
Rashi
וגר לא תונה — means, do not vex him with words (referring to the fact that he is a stranger); contrarier in old French Similar is, (Isaiah 49:26) “And I will feed them that vex thee (מוניך) with their own flesh”.
Bekhor Shor
1. YOU SHALL NOT OPRESS: since he does not know the matters of the land, it is an easy thing to oppress him.
Chizkuni
וגר לו תונה, “and you must not oppress a convert;” the reason why this verse follows that about converts serving both Hashem and their previous deities, is that G-d wishes to go on record that although He finds serving another deity as something repulsive, He does love converts and appreciates that they distanced themselves from their former religion.