What is the biblical basis for modern-day prophets? I've been seeing people lately who have claimed to be recipients of divine revelation from God (if not in that exact language) and that we all need to heed their warnings or -insert consequence here-. They say that essentially, God didn't cover everything that would ever happen in the bible, so he uses people to communicate his will to people today. Is there biblical basis for this being true? If so, how can we verify that it is from God?
The scriptures below show that God speaks through prophets, and that he will always speak through prophets.


  God Speaks Through Prophets
  
  "... Believe in the Lord your God, so shall ye be established;
  believe his prophets, so shall ye prosper." (2 Chronicles 20:20)
  
  "Surely the Lord God will do nothing, but he revealeth his secret unto
  his servants the prophets." (Amos 3:7)
  
  "Now therefore ye are no more strangers and foreigners, but
  fellowcitizens with the saints, and of the household of God; And are
  built upon the foundation of the apostles and prophets, Jesus Christ
  himself being the chief corner stone;" (Ephesians 2:19-20;)
  
  "And God hath set some in the church, first apostles, secondarily prophets, thirdly teachers, after that miracles, then gifts of healings, helps, governments, diversities of tongues." (1 Corinthians 12:28)
  
  Eternal Nature of God
  
  "Jesus Christ the same yesterday, and to day, and for ever."
  (Hebrews 13:8)
  
  "For I am the Lord, I change not; ..." (Malachi 3:6;)


Scripture is the written words of the Prophets, the Bible is the word of God spoken through prophets. God calls prophets to deliver his words to the children of men, but it is important to understand that a man can only be a prophet if he is called of God:


  "Ye have not chosen me, but I have chosen you, and ordained you, that
  ye should go and bring forth fruit..." (John 15:16)


How to verify a prophet of God

It is wise to be wary of any man that claims to have received revelation from God, especially when he claims to have received it on behalf of someone else. 


  ¶Beware of false prophets, which come to you in sheep’s clothing,
  but inwardly they are ravening wolves.  (Matt 7:15;)


Just as Christ told his disciples to go and bring forth fruit, he also promised that we can tell a man is a disciple of God by their fruits.


  16 Ye shall know them by their fruits. Do men gather grapes of thorns,
  or figs of thistles?
  
  17 Even so every good tree bringeth forth good fruit; but a corrupt
  tree bringeth forth evil fruit.
  
  18 A good tree cannot bring forth evil fruit, neither can a corrupt
  tree bring forth good fruit.
  
  19 Every tree that bringeth not forth good fruit is hewn down, and
  cast into the fire.
  
  20 Wherefore by their fruits ye shall know them. (Matt 7:16-20;)


How shall we know them by their fruits? 


  "But when the Comforter is come, whom I will send unto you from the
  Father, even the Spirit of truth, which proceedeth from the Father, he
  shall testify of me." (John 15:26)


In Galatians chapter 5, Paul explains that a true disciple of Christ is led by the Spirit, and lists the fruits of the spirit.


  22 But the fruit of the Spirit is love, joy, peace, longsuffering,
  gentleness, goodness, faith,
  
  23 Meekness, temperance: against such there is no law. (Gal 5:22;)


To know truth you must pray unto the Lord always, so that he may confirm or deny the words of any supposed prophet. If a man claims to have received a prophecy from God, and you can feel the spirit while you hear his words, then take the matter to prayer. The Spirit will confirm or deny the truthfulness of all things. If a man speaks words that cause fear and doubt, pray to know if he is a false prophet, and again the Spirit will speak the truth. Anyone that preaches fear and doubt is a false prophet.