For the verses that say “Keep listening, but do not comprehend; keep looking, but do not understand. Make the mind of this people dull, and stop their ears, and shut their eyes, so that they may not look with their eyes, and listen with their ears, and comprehend with their minds, and turn and be healed.” or similar, see Matthew 13:14 and Matthew 13:15 et al.

Note that this quote in the New Testament is not taken from the Hebrew Bible but from the Greek Septuagint (LXX) which translates to English as “Go, and say to this people: ‘You will listen by listening, but you will not understand, and looking you will look, but you will not perceive.’ For this people’s heart has grown fat, and with their ears they have heard heavily, and they have shut their eyes so that they might not see with their eyes and hear with their ears and understand with their heart and turn — and I would heal them.'” (Translation by NETS — for the Greek version see the title’s tooltip)