(Exodus, Ibid.) "he shall be put to death": (only) after having been forewarned by witnesses. You say this, but perhaps (he is put to death even) if he has not been forewarned by witnesses? It is, therefore, written (Devarim 17:6) "By the mouth (i.e., forewarning) of two witnesses" (shall one be put to death)., What, then, is the intent (here) of "he shall be put to death"? After having been forewarned by witnesses.