Speaking for Who?

"He who speaks on his own does so to gain honor for himself, but he who works for the honor of the one who sent him is a man of truth; there is nothing false about him" ~ John 7:18

How do we know if a man speaks on his own or that his message comes from God? The verse above will be a good check. Is the person gaining honor for himself? Or is he zealous for the honor of God? Think about it.