Heidegger explored how Paul's teaching on the Second Coming involved a conception of time as kairos, 'fullness of time', or moment. He discussed at length how the early Christian's relationship with God encompassed, in each moment, the temporal-existential dimensions of 'having-become' and expectant waiting-toward the future. Heidegger suggests that Kierkegaard offers 'penetrating' interpretations of the 'problem of existence' and 'the phenomenon of the moment of vision', but that in both cases his approach is 'existentiell rather than 'existential'. Heidegger's rather cursory references to Kierkegaard in Being and Time can be supplemented by his more general remarks about concept of spirit. As Heidegger indicates in the footnote to his introduction to Division Two of Being and Time, much of Kierkegaard's philosophy of existence can be understood as a response to Hegelian historicism. In Division Two of Being and Time Heidegger develops the Kierkegaardian theme of anticipation of death into more detailed and systematic account of existing authentically as a finite being.