Why are you not dealing with the verse I referenced? I know why. You're moving the goalpost. I am a student of the manuscripts and languages of the Holy Scriptures.
There are only a few references in the NT that are not taken from the LXX. You found one from Google and your mistake is trusting what you found.
You're being deceptive. Matthew 13:14-15 is a quote from Isa 6:9-10
Mat 13:14 And in them is fulfilled the prophecy of Esaias, which saith, By hearing ye shall hear, and shall not understand; and seeing ye shall see, and shall not perceive:
Mat 13:15 For this people's heart is waxed gross, and their ears are dull of hearing, and their eyes they have closed; lest at any time they should see with their eyes, and hear with their ears, and should understand with their heart, and should be converted, and I should heal them
The MT reads.
Isa 6:9 And he said, “Go, and say to this people: “‘Keep on hearing, but do not understand; keep on seeing, but do not perceive.’
Isa 6:10 Make the heart of this people dull, and their ears heavy, and blind their eyes; lest they see with their eyes, and hear with their ears, and understand with their hearts, and turn and be healed.”
Notice the problem?
"ears dull" in Matt 13 and "hearts dull" in Isa 6:10
Mark 4:12 is different. You don't know why.... Try again.