When laying the foundation for what is now known as the Christian church, Apostle Paul was pretty clear on how significant prophecy is. .

          One who speaks in a tongue edifies himself; but one who   

          prophesies edifies the church. Now I wish that you all spoke in 

          tongues, but even more that you would prophesy..(I Corinthians 14:5a).

The primary reason why Paul felt that prophesy was so critical to the Body of Christ is because prophesy is a method by which God speaks to us and encourages us.

          But one who prophesies speaks to men for edification and exhortation   

          and comfort. …… he who prophesies edifies the church                            

         (I Corinthians 14:3-4).

There is an erroneous doctrine that has been taught that says God did away with all spiritual gifts - including the gift of prophecy - when the last apostle died. This is a false doctrine that cannot be supported by scripture. On the contrary, scripture teaches the opposite.  If in fact God did away with spiritual gifts when the last apostle died, how does this teaching reconcile with this new testament scripture?

      Wherefore, holy brethren, partakers of the heavenly calling, consider the  

      Apostle and High Priest of our profession, Christ Jesus.  (Hebrews 3:1).

According to this scripture, Jesus is our Chief Apostle. Therefore, it is irrelevant to consider  when the "last Apostle" died as a demarcation for when spiritual gifts left the church because this scripture clearly states that THE CHIEF APOSTLE is Jesus Christ and HE STILL LIVES!!!!!  

And I fell at his feet to worship him. And he said unto me, See thou do it not: I am thy fellow servant, and of thy brethren that have the testimony of Jesus: worship God:for the testimony of Jesus is the spirit of prophecy. (Revelations 19:10)

Why do we need prophecy today?