they will take up serpents; and if they drink any deadly thing, it will in no way hurt them; they will lay hands on the sick, and they will recover."

Behold, I give you authority to tread on serpents and scorpions, and over all the power of the enemy. Nothing will in any way hurt you.

They were told that they should not hurt the grass of the earth, neither any green thing, neither any tree, but only those people who don't have God's seal on their foreheads.