Midrasch zu Wajikra 20:6

1) (Vayikra 10:6) "And the soul that turns to the ovoth and to the yidonim to stray after them": Why is this written? From (Vayikra 20:27) "And a man or a woman an ov or a yidoni … with stones shall they stone them," we hear the punishment. Whence do we derive the exhortation? From (Vayikra 19:31) "Do not turn to the ovoth and to the yidonim." We hear the punishment and the exhortation, but we have not heard kareth (cutting-off). It is, therefore, written "And the soul that turns to the ovoth and to the yidonim … I shall cut him off from the midst of his people."