2 Chronicles 19-21

In chapter 18 it is recorded how Jehoshaphat realized the 400 prophets whom Ahab assembled were not speaking for the LORD. In chapter 20 Jehoshaphat gathered a multitude to plead with their God. When he had finished praying and was waiting before the LORD one man spoke up. Scripture doesn't indicate that Jahaziel was recognized as a phrophet. But Jahaziel felt led to speak a message of confidence before the crowd and the king. When he had finished speaking the king accepted Jahaziel's words as being inspired and acted on them. But what was it about the words and the speaker that legitimized the message in the king's heart? He spoke in the name of the LORD. He was very specific in his instructions. But maybe the point that convinced Jehoshaphat was that the message called for faith as well as action. Deliverance was promised to come from the LORD not the army of Judah. I don't know if those were the words that convinced the King but when he acted accordingly God did provide. 
It took me about 12 minutes to read this passage.
Stuart