The Spanish origins of the Society of Jesus entailed a sensitivity about the Jewish ancestry of many of its members. This article examines the decision taken by the Fifth General Congregation of the Society (1593–1594) to exclude persons of Jewish descent (conversos), in light of strong criticism voiced by three leading Jesuits: Robert Persons (1546–1610), superior of the English mission, Diego de Guzmán (c.1522–1606), a noted Spanish preacher and catechist, and Antonio Possevino (1533–1611), an Italian Jesuit involved in high-level diplomacy. This article analyses selected correspondence in which they confronted the superior general, Claudio Acquaviva (1543–1615, in office 1580–1615), questioning the argument that conversos inhibited the work of the Society. The writers’ rhetorical strategies include logical argument and practical demonstration as well as appeals to ethos and pathos through personal experience and dramatised precedent, hoping to shame the general into moderating the policy. Acquaviva’s resistance to their persuasion is explained by his need to retain the support of the Spanish royal court in asserting his authority over dissident Jesuits in Spain as well as to sustain his project to increase the effectiveness of the Society through internal coherence and tight organisation.Contribution: The article illustrates the use of rhetorical strategies to reinforce the biblical principle of racial equality within the Society of Jesus in the Reformation era.