Charles Ellicott Commentary Mark 16:18

"they shall take up serpents, and if they drink any deadly thing, it shall in no wise hurt them; they shall lay hands on the sick, and they shall recover." — Mark 16:18 (ASV)

They shall take up serpents.—The instance of St. Paul at Melita is the only recorded example of the kind (Acts 28:1–6). Power over serpents and scorpions had, it will be remembered, been given before (Luke 10:19).

If they drink any deadly thing . . .—Of this there is no recorded instance in the New Testament, but it finds an illustration in the tradition of the poisoned cup which was offered to St. John.