Halakhah su Levitico 19:33

To not oppress the convert with words: That we have been prevented from oppressing converts, even [only] with words - and that is one from the [other] nations who converted and entered our religion - such that is forbidden for [one] to disgrace him even with words, as it is stated (Exodus 22:20), "and you shall not oppress a convert." And even though we are warned about this with [Jews] and since this one entered our religion, behold is like [any other Jew], Scripture added a warning to us and also redoubled the prohibition for him, as it is written (Leviticus 19:33), "do not oppress" another time; because the issue of oppression is more relevant to a convert than it is to [another Jew], as [another Jew] has redeemers who will redress his insult. And there is another reason, [and that is] because there is a concern that [the convert] might return to his deviance out of anger over the disgraces. And they said in the Sifra (Sifra, Kedoshim, Chapter 8:2) that one shouldn't say, "Yesterday you were an idolater and now you entered under the wings of the Divine Presence."

The obligations of Jews, individually and collectively, with regard to converts are not limited to concern for their spiritual welfare and essential temporal needs. Mahari Perla, in his commentary to Sa'adia Ga'on's Sefer ha-Mizvot (Aseh, no. 82), writes that Sa'adia viewed the passage "And if there would dwell among you a proselyte in your land … as the home-born among you shall the proselyte who dwells among you be unto you, and you shall love him as yourself …" (Lev. 19:33–34) as constituting a positive precept. In commanding that the treatment accorded a proselyte be identical with that accorded the native-born Jew, the Torah expressly forbids any type of discrimination whatsoever. Any form of prejudice, whether expressed in word or deed, constitutes a violation of this precept. The Torah does not countenance discrimination against converts; nor does it tolerate discrimination among righteous proselytes on the basis of color.

He prohibited us from wronging the convert with words. And that is His stating, "You shall not wrong a convert" (Exodus 22:20). And the prohibition was repeated with His saying, "you shall not wrong him" (Leviticus 19:33). And in the Sifra (Sifra, Kedoshim, Chapter 8:2): "You shall not say to him, 'Yesterday you worshipped idolatry, and now you have entered under the wings of the Divine Presence.'" (See Parashat Mishpatim; Mishneh Torah, Sales 14.)