The article proves that the philosophical system of L.P. Karsavin has a number of concepts borrowed from Kabbalah as a basis. Karsavin describes the relationship between God and the world in accordance with the concept of tzimtzum, according to which God limited himself in a certain sphere in order to give place to created being. Karsavin's concept of evil and his idea of Adam Kadmon as the original integral, divine state of man also have Kabbalistic origins. The article expresses the conviction that the use of Kabbalistic ideas does not contradict Karsavin's statements about the Christian nature of his philosophy. By true Christianity (Orthodoxy), he means the Gnostic teaching, which was initiated by Basilides and Valentinus. Karsavin regards the tradition of Russian religious philosophy to which he belonged as an adequate and complete philosophical expression of the indicated Gnostic teaching and as an absolute form of religiosity that can unite the true, final forms of all religions, including Kabbalah, as the final form of Judaism.