During the crisis that followed the disintegration of the kingdom, God did not abandon His people and the plan of salvation of the world. So he invited some people, gave them a deep knowledge of His will, and assigned them to a great task: to make his will known to people. These were the prophets.
The prophet Ezekiel writes for his calling:" When I saw the glow, I fell face down on the ground. And then I heard the voice of someone talking ... "Man, I send you to the Israelites, to the nation ... who has rebelled against me ... to convey to them what I, the Lord, have to say to them. Whether they listen to you or not ... they will learn that there is a prophet among them. But man, do not be afraid of them or their words ... You will tell them my words, whether they hear it or not ... ".
Therefore the prophets were sent to mediate between the true God and His people. And because their mission was difficult, some people were hesitant at first. In the end, however, they all fully trusted God, overcame their fears, and thunder out the truth about His will. They always started preaching with the words: "God our Lord says ..." or "the word of our Lord is...".