[4:93] And whoever slays a believer deliberately, his requital is Hell, abiding therein, and God is wroth with him and has cursed him, and has prepared for him a mighty chastisement.
Just as the killing of another has been prohibited to you, killing yourself is prohibited to you. Whoever follows his whims seeks the blood of his self. Whoever does not give good counsel and admonition to an aspirant, and does not assist him in his endeavor, has sought his blood. He is trapped by his own situation. It is natural that his outcome is unpleasant in that he cannot enjoy what he has held back from the aspirants in his states. Indeed, He (s) said: O David, when you see someone seeking me, be his servant.