Death is Dasein’s ownmost possibility. Being towards this possibility discloses to Dasein its ownmost potentiality-for-Being, in which its very Being is the issue.
This passage delivers Heidegger’s definitive formulation: Being-towards-death is not avoidance of an end but the authentic disclosure of Dasein’s individuation and the ground of genuine selfhood.
, Being and Time, 1962thesis