Career
Despite persecution, he remained true to his convictions, although he was robbed of his possessions and reduced to poverty. He was chosen rabbi by the community of Ávila. Moses was acquainted with the Christian sources, and refuted in four debates the arguments of his opponent, who tried to prove the Christian dogmas from the Scriptures.
Soon afterward he was obliged to enter upon a new contest with a disciple of the convert Abner of Burgos, with whose writings, especially with his Mostrador de Jeosticia, Moses was thoroughly acquainted.
His book, which is divided into seventeen chapters, dealing with 125 passages emphasized by Christian controversialists, is entitled ""Ezer ha-Emunah" (The Support of Faith אמונה). lieutenant was sent by its author to David ibn Ya"ish at Toledo, and manuscripts of it are found at Oxford, Berlin, Parma, Breslau, and elsewhere.
Moses ha-Kohen made strong use of the theory in the defence of Yechiel of Paris at the Disputation of Paris in 1240 that there were two Jesuses - the Jesus in the Talmud, and the Jesus of the New Testament. Isidore Loeb (1888) showed that Moses ha-Kohen followed on from the pioneering works such as Shem Tov Shaprut"s The Touchstone, Joseph Kimhi"s Sefer ha-berit and most of all Jacob ben Reuben"s Milhamot ha-Shem.
lieutenant also shares common ground with later works such as The refutation of the Christian principles of Hasdai Crescas.