And these signs will accompany those who believe: In My name they will drive out demons; they will speak in new tongues; they will pick up snakes with their hands, and if they drink any deadly poison, it will not harm them; they will lay their hands on the sick, and they will be made well
Mark 16:17 exists only in the "longer version" of Mark and was not part of the original gospel of Mark; it was added much later. This verse does not appear in the manuscript evidence in the first 300-years of the common era. The first Bible to include this verse was Codex Washingtonianus dated to the 5th century.
Therefore, 400-years after Jesus and the Bible was finalised, Christian scholars were 'inventing' entire verses and inserting them into the canon Bible.