Isaiah 6:9-10
And He said, “Go, and tell this people:
‘Keep on hearing, but do not understand;
Keep on seeing, but do not perceive.’
“Make the heart of this people dull,
And their ears heavy,
And shut their eyes;
Lest they see with their eyes,
And hear with their ears,
And understand with their heart,
And return and be healed.”

At first glance, it seems God is commanding the people to ignore His word from the prophet. Phrases like “make the heart of this people dull” seem to indicate God wants them not to hear.
That’s not the case.
Jesus quoted this in Matthew 13:11-17, right after the disciples asked Him, “Why do you speak in parables?”
Jesus spoke the word of God during His ministry, as did Isaiah. The word both spoke angered many while others just ignored it, thus fulfilling this scripture.
It continues to happen today.
I preach and teach the word and though it’s not true of all, there are some that hear what is said but ignore it. Others hear what is said and argue about it.
That’s not unique to me. It happens to most ministers.
The truth is what Isaiah and Jesus both said is people hear the preached word, see the outpouring of the Holy Spirit, or witness a miracle and they close their ears and shut their eyes against it.
Why?
Because to admit to the truth of these things would lead them to admit their own sin and accept the need for a Savior.
They fear the change salvation would make. They are content to wallow in sin so they close their ears and eyes to the truth.