1 Corinthians 12:3 Wherefore I give you to understand, that no man speaking by the Spirit of God calleth Jesus accursed: and that no man can SAY that Jesus is the Lord, but by the Holy Ghost. No one can say the phrase unless under the direction/inspiration/permission of the Holy Spirit. The text does not limit or infer the "saying" to a man who properly understands what he is saying. If a Mormon says the phrase it is by the direction of the Holy Spirit. A devil may know that Jesus is Lord but this passage infers he can not SAY it out loud.