They shall take up serpents; and if they drink any deadly thing, it shall not hurt them; they shall lay hands on the sick, and they shall recover.
Note 14 at Mr 16:18: This is either speaking literally of supernatural protection if we pick up a snake or symbolically of protection in our fight against the devil. Since the other four signs in this list are literal, it is most probable that this is speaking of physically taking up snakes.
The Apostle Paul experienced this supernatural protection from a viper when he was shipwrecked on the island of Melita (Ac 28:3-5). However, this is the only recorded example of this in the New Testament. There is no record of the disciples picking up snakes just to prove they were believers. That would be tempting God (Lu 4:9-12). This, as well as drinking any deadly thing, is a promise that if we pick up snakes accidentally or are forced into that position because of our stand for Christ, we can believe for supernatural protection.
Note 15 at Mr 16:18: As explained in note 14 at Mr 16:18 about taking up serpents, this does not mean that we can tempt God by drinking poison just to see if this promise works.
Note 16 at Mr 16:18: Jesus gave all believers (not just ministers) the power to heal the sick through the laying on of hands. Since it is His power that we are using and not our own, we should expect to get the same results.
Note 17 at Mr 16:18: The laying on of hands is an important doctrine in the New Testament (Heb 6:2). We can actually transmit the power of God through laying our hands on people in the same way that power can be transferred from one battery to another through cables. This doesn't work for everyone though, only for those who believe.