Jesus warns his community that false prophets will arise and will be difficult to detect because they would proclaim his name. In the Old World, many taught Christianity and proclaimed themselves to be prophets. All of them spoke of the name of Christ. What mattered was whether they spoke in the name of Christ.
Book of Mormon Context: Like the section on false prophets, this saying would have had little relevance to the Nephites.
Comparison: There are no changes from the Matthean text.