PROPHECY is not mysterious, all that prophecy speaks of in it's various ways is the redeeming work of Jesus Christ, His Victory on the cross on our behalf, 

The testimony or witness of Jesus is the spirit of prophecy, the bible says. The Spirit of God has only but one song and it's the song of our salvation, our deliverance, the wonderful and glorious works of Jesus.

And as we pray in the spirit, God brings to our knowledge and in our language, the songs, poetry, utterances of our Eternal Victory in Christ. And that my friend, is Prophecy, inspired words, tongues and interpretation.

This words when spoken out is God talking! you see why you should prophesy? it's Glorious!