<P> The term `` poisoned chalice '' is applied to a thing or situation which appears to be good when it is received or experienced by someone , but then becomes or is found to be bad . The idea was referred to by Benedict of Nursia in one of his exorcisms , found on the Saint Benedict Medal : Vade retro Satana ! Nunquam suade mihi vana ! Sunt mala quae libas . Ipse venena bibas ! ( Begone Satan ! Never tempt me with your vanities ! What you offer me is evil . Drink the poison yourself ! ) . William Shakespeare uses the expression in Act I Scene VII of Macbeth . It occurs in the opening soliloquy of the scene when Macbeth is considering the ramifications of the murder he is plotting . </P>
where does the phrase poison chalice come from
Benedict of Nursia in one of his exorcisms