Deuteronomy 15:3

Ver. 3. Of a foreigner thou mayest exact it again— Of an alien, that is, one who was neither a native Israelite, nor proselyted to the Jewish religion, but a mere Gentile: for this was one of the privileges of the Jewish community, and not one of the common rights of mankind; and therefore it is restricted wholly to Jews or Gentile proselytes: besides, there was not the same reason for releasing the principal or interest to a foreigner as to a Hebrew; for the Hebrews observed the sabbatical year, whereas the other sowed and reaped and traded in that year, as well as in others. See Grotius and Le Clerc.