the Shlichim history 28:26-27

go to the this people and say: with the hearing will you (PL) hear and not understanding be; and looking will you (PL) look and not see; because dull/fat become is the heart of the this people, and with the ears hear they with difficulty, and the eyes their have they shut, lest would they see with the eyes, and with the ears hear, and would understood with the heart and repentance do (to way of Hashem), and I would them heal. (Yeshayah 6, 9-10)