"Until cities lie waste
without inhabitant,
and houses without people,
and the land is utterly desolate;
12 until the Lord sends everyone far away,
and vast is the emptiness in the midst of the land.
13 Even if a tenth part remains in it,
it will be burned again,
like a terebinth or an oak
whose stump remains standing
when it is felled.’
The holy seed is its stump.
Growing up this was taught to me that God would make the people deaf and dumb and then because of their deafness and dumbness God would destroy the city.
I would offer up that the deafness, dumbness and destruction is not from God but from the people. Here is what I mean.
God tells the prophet to listen but do not comprehend, look but do not understand. What is God asking them to listen and look at? God is asking them to listen and look at the way the people are acting toward one another. The land lacked justice and compassion and as a result the people were full of bitterness and hatred toward one another. It was taught by the culture of this time that the only person that mattered was their little tribe. It was taught that to give handouts was a waste of time and enabling freeloading. It was taught that foreigners were dangerous and that you cannot trust anyone.
As such, God desired for the people of Israel to look and listen to these cultural messages but to not understand, comprehend or embody them. For the cultural values of "self first" were destructive. God desired the people to turn from these selfish ways and be healed.
Isaiah was to preach this message of looking but not understanding until the city lay in ruin. God does not cause the city to fall and people to be homeless, but this desolation was the direct result of their selfish behavior. So keep preaching the message of see but do not embody until the selfish behavior has cannibalized itself. Do not fall prey to this selfish way of life for it leads to destruction. Even is just a little bit of self serving behavior is left in the culture, it will continue to cause destruction. Selfishness, greed and inhospitable are powerful forces for destruction and must be allowed to burn themselves out.
Thus those who remain, those who do not burn themselves out from greed and fear, this group will be the stump by which God's grace and mercy will grow from.