Jeremiah 5:13

And the prophets shall become wind, and the word is not in them: thus shall it be done unto them.

In its setting the people and their rulers persisted in wickedness and denied the Lord. They dismissed warnings of sword and famine, refusing to heed what had been announced against them. The prophets becoming wind means they had no true word or message from God, and their claims were empty like wind. The verse belongs to a warning that Jerusalem could have been spared if the people had turned to the Lord and obeyed, but their refusal brought the announced Babylonian destruction and captivity.

Because the prophets were empty, God's announced warnings of judgment would fall upon the people themselves. God's word would become fire in the prophet's mouth to consume the people as judgment fell on them. The picture of injustice and disregard for truth applies to both ancient Israel and the present.