The 255th prohibition is that we are forbidden from hurting the feelings of this servant1 who has run away to us.
The source of this prohibition is G‑d's statement2 (exalted be He), "He must be allowed to live alongside you wherever he chooses in your settlements. You must do nothing to hurt his feelings."
In the words of the Sifra3: "The phrase 'You must do nothing to hurt his feelings' refers to ona'as devarim."4 In the case of a convert, G‑d (exalted be He), added an extra prohibition of ona'as devarim due to his feeling of extreme humility and his status as a convert. In this case of a servant, who feels even more lowly and humble than a [regular] convert, G‑d added a third prohibition,5 in order that we should not say that "this servant doesn't mind ona'as devarim."6
It is clear that the servant referred to by the verse and the convert mentioned in the prohibition of ona'as devarim have both accepted upon themselves the Torah, i.e., they are gerei tzedek.7
