The message that there would be ravenous wolves who would lead the faithful away from the path was serious enough that Jesus continued along that theme. Part of the sheep’s clothing is that there would come those who would promote their ideas by declaring that they are preaching Christ. They might pray to him. They might invoke His name. However, if they are not a good tree, they cannot provide the good fruit. Therefore, Christ notes that even though they might appear to follow him, he does not recognize them (“I never knew you”).