What does the verse discuss coming?
Rashi: The evil [that was predicted].
What do we learn from "Hine Va'ah"?
Rashi, Radak: They think that your prophecies are mockery and jest. When they will come true ? this will be soon - they will know that there was a true Navi among them.
Malbim: The Navi's prophecies for the future and his warning that punishments will come upon them, they do not heed him and do not believe his words, until the punishments will come. Then there is no benefit that they heard the Navi's words, for they did not repent to evade the evil! The benefit is only so they will know afterwards that there was a Navi among them and then they will believe that it is true Nevu'ah, but then they cannot fix the evil past.