When discussing protective laws, the Torah states, “VeGeir Lo Toneh VeLo Tilchatzenu Ki Geirim Heyitem BeEretz Mitzrayim,” "You shall not abuse a stranger and you shall not oppress him, for you were strangers in the land of Egypt" (Shemot 22:20). Rashi states that if a Jew bothers a Geir, or convert, the Geir can respond by noting that Jews also descended from strangers, for their ancestors were strangers in Egypt; therefore, they should not accuse the converts about a fault which they have, too. Rashi concludes by defining “Geir” as a person who had not been born in the land where he dwelled. What compelled Rashi to define “Geir,” a common word used throughout the Torah?
One can answer by noticing the difference between two types of Geirim. Residing in Israel and committed to observing the Seven Noahide Laws, a Geir Toshav is a gentile, whereas a Geir Tzedek is a full-fledged Jew. Rashi was thus compelled to define “Geir,” as the word has two different meanings and could create confusion. Obviously, we were not converted Jews, or Geirei Tzedek, in Egypt, but were strangers in a strange land, so the Pasuk must deal with a Geir Toshav. If, however, the Jews were strangers but not converts, why are we are commanded elsewhere (see Bava Metzia 58b) not to oppress converted Jews as well? Dr. Avigdor Bonchek answers by quoting the Gemara (Bava Metzia 59b), which says that one should not say “hanging” to a person who convicted a relative to death by hanging, as the word scares him and we must be sensitive to his feelings. Likewise, the Torah is telling us to be sensitive to a Geir, because as long as our Geirut status is similar to his, we are also vulnerable to taunts; thus, Jews, of all people, must be sensitive to a convert’s vulnerable position.