From 2 Chronicles 17-19...
King Ahab loved his false-prophets because they always said good stuff about him. All 400 yes men would would stand and tell him how much God approved of his plans, loved him and would bless him. Always encouraging, always affirmative. True prophecy in contrast can be both encouraging and convicting, affirming and correcting.
Above all it includes messages like that of Micaiah to Ahab... That true prophet told Ahab that his people were sheep without a shepherd. They had no king. They were like the people in the days of the judges - unruly and unruled. Self-ruled and doing whatever they felt like. They were people in need of a true king, the true king.
It's here that Micaiah is proved a true prophet - his word is one that proclaims the need for God's King to rule. In Ahab's case he exposes that the Messiah has not yet come. Neither Ahab, or Jehoshaphat for that matter, are Great David's Greater Son. They had to keep waiting... Ahab failed to listen and so he died. Judged by God through the King of Syria and the 'random' shot of a soldier.
Jesus repeats the observation of God's people being sheep without a shepherd. He looks on the crowds and sees their need to come and live under His rule. In Jesus the king has come. His kingdom is near, and when he returns it will be fully manifest. Paul writes to the Corinthians to tell them that the Holy Spirit leads people to confess that Jesus Christ is Lord - declaring the Kingly rule of Jesus.
That's true prophecy. Fixing our eyes on the everlasting rule of God's King. That rule is comforting. That rule directs our footsteps. Gospel prophets are what the church needs. This is the prophecy we need to eagerly desire.