# He said, 'Go to this people and say, "Hearing you will hear, but you will never understand; seeing, you will see, but you will never know.

"The Spirit told Isaiah to go tell them that they will hear but will not understand and they will see but they will not know" 

# Hearing you will hear ... seeing, you will see

The words "hear" and "see" are repeated for emphasis. "You will listen carefully ... you will look intently"

# but you will never understand ... but you will never know

Both of these phrases mean basically the same thing. They emphasize that the Jewish people will not understand God's plan.