1. The notion and the discussion. For the word “unbelief’ (ἁחίστία incredulitas) see, for example, Mt 13:58; Mk 9:24; Rom 3:3; 4:20; 11:20, 23; Heb 3:11, 19. Unbelief is the deliberate rejection of faith. It is presupposed that faith and unbelief (in the case of men capable of a decision) are not two possibilities among others, but that everyone either believes or refuses to believe and that there is no way of avoiding this choice. When the concept is so defined, the question at once arises as to whe…