This I say therefore, and testify in the Lord, that ye henceforth walk not as other Gentiles walk, in the vanity (futility) of their mind, having the understanding darkened...
(Ephesians 4:17-18)
Blessed is the man that walketh not in the counsel of the ungodly...
(Psalm 1)
Definitely a prophecy. Clear and PLAIN. No doubt about it.
Some of the greatest prophecies in the Bible are predictive statements out of the mouth of a Prophet.