After these things he appeared in another form to two of them, as they were walking into the country.  And they went back and told the rest, but they did not believe them.
 Afterward he appeared to the eleven themselves as they were reclining at table, and he rebuked them for their unbelief and hardness of heart, because they had not believed those who saw him after he had risen.  And he said to them, “Go into all the world and proclaim the gospel to the whole creation.  Whoever believes and is baptized will be saved, but whoever does not believe will be condemned.  And these signs will accompany those who believe: in my name they will cast out demons; they will speak in new tongues;  they will pick up serpents with their hands; and if they drink any deadly poison, it will not hurt them; they will lay their hands on the sick, and they will recover.”
 So then the Lord Jesus, after he had spoken to them, was taken up into heaven and sat down at the right hand of God.  And they went out and preached everywhere, while the Lord worked with them and confirmed the message by accompanying signs.]]
(Mark 16:9-20 ESV)
With these words in mind, I thought instead of taking four days to complete Mark I would simply take all these extra verses and do them all at once. :)
Jesus, when he rose early, appeared first to Mary Magdalene, and she went and told the others....but they didn't believe her.
Jesus also appeared to two others as they walked along the road in the country. These two also reported this fact to the disciples but again, were not believed.
Then Jesus appeared to the 11 as they were sitting around a table, he rebuked them for their lack of faith because they didn't believe the reports of Mary and the two men.
Jesus then gave them this command "“Go into all the world and proclaim the gospel to the whole creation. Whoever believes and is baptized will be saved, but whoever does not believe will be condemned. And these signs will accompany those who believe: in my name they will cast out demons; they will speak in new tongues; they will pick up serpents with their hands; and if they drink any deadly poison, it will not hurt them; they will lay their hands on the sick, and they will recover.”
Then the Lord, having given them this final injunction, was taken into heaven, where he sits on the right hand of God.
The disciples went out and did what they were bidden, the Lord worked with them, and confirmed their message with signs.
I have to admit, I can see what people would wonder if this section belongs in the bible or not. It reads differently than the rest of Mark.
Regardless of the uncertainty, it is still part of the the bible and the injunction is clear. We are to tell others about the Lord, this is clear from supporting scriptures. Believe, be saved. Don't believe, be condemned. Proclaim the gospel, help others believe in God.
I know that there are people who use the last part of Jesus' command in odd ways... who deliberately handle poisonous snakes, who drink poisons and what not. But I think they fail to see that those are SIGNS, not givens. They are signs from God not of your faith but of your obedience when you go out proclaiming the word of God. The two go together, not meant for private gatherings or for showing off or for proving your faith.