Jost appeared repeatedly as an apologist of Judaism against political reactionaries and detractors of rabbinical literature; his "Was Hat Herr Chiarini in Angelegenheit der Europäischen Juden Geleistet?" (Berlin, 1830) was directed against Abbé Chiarini's "Théorie du Judaïsme"; and his "Offenes Sendschreiben an den Geheimen Oberregierungsrath Streckfuss" (Berlin, 1833), against Streckfuss' "Verhältnis der Juden zu den Christlichen Staaten." When in the beginning of the reign of Frederick William IV of Prussia the rumor was spread that the king contemplated an alteration of the legal position of the Jews in a reactionary sense, Jost wrote "Legislative Fragen Betreffend die Juden im Preussischen Staate" (Berlin, 1842) and "Nachträge zu den Legislativen Fragen" (Berlin 1842). Between 1839 and 1841 he edited the "Israelitische Annalen", a weekly chiefly devoted to the collection of historical material, and between 1841 and 1842 the Hebrew periodical "Zion" (in collaboration with his friend and colleague Michael Creizenach). He was also a frequent contributor to the Jewish press, to almanacs, and to year-books.