Isaiah 6:10
9 He said, “Go and tell these people: “‘Listen continually, but don’t understand. Look continually, but don’t perceive.’ 10 Make the hearts of these people calloused; make their ears deaf and their eyes blind. Otherwise they might see with their eyes and hear with their ears, their hearts might understand and they might repent and be healed.” 11 I replied, “How long, Lord?” He said, “Until cities are in ruins and unpopulated, and houses are uninhabited, and the land is ruined and devastated,
Zechariah 7:11
10 You must not oppress the widow, the orphan, the resident foreigner, or the poor, nor should anyone secretly plot evil against his fellow citizen.’ 11 “But they refused to pay attention, turning away stubbornly and stopping their ears so they could not hear. 12 Indeed, they made their hearts as hard as diamond, so that they could not obey the law of Moses and the other words the Lord of Heaven’s Armies had sent by his Spirit through the former prophets. Therefore, the Lord of Heaven’s Armies poured out great wrath.
Notes and References
"... The phrase ('make the ear dull') occurs in the Old Testament only in Isaiah 6:10 and Zechariah 7:11. Besides these two passages, the hiphil occurs in this meaning only in Exodus, where it is used four times to describe Pharaoh's heart. In Isaiah, the prophet is told to make the people's ears dull, whereas in Zechariah the people are blamed for having made their ears dull ..."
Nurmela, Risto "The Growth of the Book of Isaiah Illustrated by Allusions in Zechariah" in Boda, Mark J., and Michael H. Floyd, (ed.) Bringing out the Treasure: Inner Biblical Allusion in Zechariah 9-14 (p. 250) Sheffield Academic Press, 2003