Yirmiyahu hears the words of Chananya which negate his prophecy. He does not counter them, but merely warns Chananya against false prophecy. Moreover, Yirmiyahu who loves his people with all his heart, hopes and wants to believe that his own prophecy of calamity will be cancelled. Only after God speaks to him does he know that Chananya's speech was a false prophecy. A true prophet is aware of the possibility of change and of the dynamic quality of prophecy.
The decree is not fixed and absolute, but rather dynamic and conditioned on the situation.
In contrast, Chananya presents the opposite position. He extrapolates from prophecies he heard from others and attempts to draw conclusions from them. The falseness in his prophecy stems from his failure to understand that God's word does not fit every generation in the same way. In this regard, he is the total opposite of Yirmiyahu, the true prophet.
Abridged and adapted by HaTanakh.com Staff. For further reading, see the full article.