Is this Bible verse about believers and poison to be taken literally?

Mar 16:20 And they went forth, and preached every where, the Lord working with [them], and confirming the word with signs following.

...and confirming the word with signs following.

Mar 16:18 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.

This seems to say to me that at least some of the Christian preachers and priests should be able to drink poison without any harm, even if the followers are exempted.

I want to see it for myself, not be assured that it happened but can't be shown now.

Act 28:3-6 And when Paul had gathered a bundle of sticks, and laid [them] on the fire, there came a viper out of the heat, and fastened on his hand. And when the barbarians saw the [venomous] beast hang on his hand, they said among themselves, No doubt this man is a murderer, whom, though he hath escaped the sea, yet vengeance suffereth not to live. And he shook off the beast into the fire, and felt no harm. Howbeit they looked when he should have swollen, or fallen down dead suddenly: but after they had looked a great while, and saw no harm come to him, they changed their minds, and said that he was a god.

Matthew Henry
Bible Search and Study Tools - Blue Letter Bible3. What power they should be endowed with, for the confirmation of the doctrine they were to preach (v. 17); These signs shall follow them that believe. Not that all who believe, shall be able to produce these signs, but some, even as many as were employed in propagating the faith, and bringing others to it; for signs are intended for them that believe not; see 1 Co. 14:22. It added much to the glory and evidence of the gospel, that the preachers not only wrought miracles themselves, but conferred upon others a power to work miracles, which power followed some of them that believed, wherever they went to preach. They shall do wonders in Christ’s name, the same name into which they were baptized, in the virtue of power derived from him, and fetched in by prayer. Some particular signs are mentioned;(1.) They shall cast out devils; this power was more common among Christians than any other, and lasted longer, as appears by the testimonies of Justin Martyr, Origen, Irenaeus, Tertullian Minutius Felix, and others, cited by Grotius on this place.(2.) They shall speak with new tongues, which they had never learned, or been acquainted with; and this was both a miracle (a miracle upon the mind), for the confirming of the truth of the gospel, and a means of spreading the gospel among those nations that had not heard it. It saved the preachers a vast labour in learning the languages; and, no doubt, they who by miracle were made masters of languages, were complete masters of them and of all their native elegancies, which were proper both to instruct and affect, which would very much recommend them and their preaching.(3.) They shall take up serpents. This was fulfilled in Paul, who was not hurt by the viper that fastened on his hand, which was acknowledged a great miracle by the barbarous people, Acts 28:5, 6. They shall be kept unhurt by that generation of vipers among whom they live, and by the malice of the old serpent.(4.) If they be compelled by their persecutors to drink any deadly poisonous thing, it shall not hurt them: of which very thing some instances are found in ecclesiastical history. {I wish he had referenced some -F}(5.) They shall not only be preserved from hurt themselves, but they shall be enabled to do good to others; They shall lay hands on the sick, and they shall recover, as multitudes had done by their master’s healing touch. Many of the elders of the church had this power, as appears by Jam. 5:14, where, as an instituted sign of this miraculous healing, they are said to anoint the sick with oil in the name of the Lord. With what assurance of success might they go about executing their commission, when they had such credentials as these to produce!

Are we not in the same crisis of faith? It's even pointed out by Phat in his post about modern culture.Where are the poison drinkers that should be showing us that God is here and we should accept his word? Are we less important than the people He was trying to convert so many centuries ago?

Well, Deuteronomy in the OT and the passage I am quoting is from the NT.Wouldn't most Christian Biblical Literalists give more weight to the NT?

But to go out and look for poison that I may tempt God, why on earth would that prove anything? It was given to those preachers BECAUSE they were preaching, and that would prove the Lord was with those believers. Ans they were in places where they could come to harm, and lay hands on many sick.

You are sure it is saying that ALL Christians ALWAYS will exhibit these immunities to dangers, and that since all obviously don't, the passage is false.

but I can also see God saying, Look, you've had the gospel in America since the Mayflower,

I understand where you're coming from, Faith (at least I think I do).
I suppose I just feel that the crisis that Christians of today's world face is not much different from what was experience in yesterday's time. To me, it seems like a God that was so involved and passionate about believing and faith, who was doing all he could (even sending his only begotten son) has since left us.Why?

Is there anything to indicate that his plan was to set the wheels of the church in motion and then let them ride out without further involvement?