ישעיהו ו:יא פירוש: רש״י ואבן עזרא

Until when will they make their heart heavy and not listen?

How long. The prophet wants to know how long this misfortune shall last, that the people shall not understand nor repent. The answer is, Till the land be desolate.

And He said I know that they will not repent until retribution comes upon them and they go into exile, and the cities will be desolate without inhabitants.