Prophets speak for God.
Matthew 4:3 “Now when the tempter came to Him, he said, ‘If You are the Son of God, command that these stones become bread.’”
Jesus was not being tempted by a prophet.
4 The Spirit clearly says that in later times some will abandon the faith and follow deceiving spirits and things taught by demons. 2 Such teachings come through hypocritical liars, whose consciences have been seared as with a hot iron.
(1 Timothy 4 (NIV)