His knowledge of the Latin and Polish languages and of Christian dogmatics enabled him to engage in amicable conversations on religious subjects not only with Roman Catholic, Protestant, and Greek Orthodox clergymen, but also with Socinian and other sectarian elders. The fruit of these personal contacts, and of Isaac Troki’s concurrent extensive reading in the New Testament and the Christian theological and anti-Jewish literature, was his famous apology of Judaism entitled Hizzuk Emunah (Fortification of Faith). He himself did not live to complete it, but his pupil, Joseph Malinovski Troki, supplied the preface and index from the author’s own written notes and oral remarks.