Mark 16:18

They shall take up serpents

(οφεις αρουσιν). Jesus had said something like this in Luke 10:19 and Paul was unharmed by the serpent in Malta (Acts 28:3).If they drink any deadly thing

(κ'αν θανασιμον τ πιωσιν). This is the only N.T. instance of the old Greek word θανασιμος (deadly). James 3:8 has θανατηφορος, deathbearing. Bruce considers these verses in Mark "a great lapse from the high level of Matthew's version of the farewell words of Jesus" and holds that "taking up venomous serpents and drinking deadly poison seem to introduce us into the twilight of apocryphal story." The great doubt concerning the genuineness of these verses (fairly conclusive proof against them in my opinion) renders it unwise to take these verses as the foundation for doctrine or practice unless supported by other and genuine portions of the N.T.