I am having a conversation with someone who says they believe in Sola-Scriptura, but doesn't believe that a gift such as prophecy adds to the Bible.
I am including his exact quote, just so what he is saying is understood. I am trying to formulate a good answer to him; however I can't seem to think of a good way to answer him.
Any help I can get on that would be helpful.

Quote
I agree with you absolutely. Anyone would be a fool to argue against what God has decreed. But there’s a problem…is the prophet Joel whom Peter quotes in Acts 2:17-18 (Joel 2:28-31) a false prophet? Did Peter unwittingly spread false teachings? Or is it possible that God will do what God will do through His Spirit whenever He pleases? Why would prophesy today be an “addition” to what is already in scripture? Could prophesy today not be truths and revelations that serve only to buttress God’s holy and unpassing Word?

Tom