before the time

 [28] And when he was come to the other side into the country of the Gergesenes, there met him two possessed with devils, coming out of the tombs, exceeding fierce, so that no man might pass by that way.
[29] And, behold, they cried out, saying, What have we to do with thee, Jesus, thou Son of God? art thou come hither to torment us before the time?

 

How do the demons know it's "before the time"? Is it a guess? Jesus said that no one knows the time, only the heavenly father.