Partly, for the prevention of monstrous births; partly, to blot out the memory of so loathsome a crime; and partly, that by so severe a punishment of that creature which was only a passive instrument to man's sin, men might be assured that a more dreadful punishment than corporal death was reserved for them, if they repented not.
Related Commentaries of Leviticus 20:15
Leviticus 20:15
15 And if a man lie with a beast, he shall surely be put to death: and ye shall slay the beast.