Matthew 13:15

“For this people's heart is grown gross, and their ears are dull of hearing, and their eyes they have closed, lest it happen that they should perceive with their eyes, and hear with their ears, and understand with their heart, and should turn again, and I should heal them.”

The reason for their failure is because of the condition of their ‘inner hearts', that is, their minds, emotions and wills. Their hearts and minds and thoughts are full of other things so that they have become fat and dull and lazy as far as God is concerned, their ears are attuned to other things and therefore they give no credence to spiritual things, they close their spiritual eyes when they are challenged about God so that nothing comes home to them, and this is what prevents their hearing, and seeing, and understanding with the result that they do not ‘turn again'. Thus no genuine response results in their lives, and Jesus therefore does not heal them.

“Lest it happen that they should perceive with their eyes, and hear with their ears, and understand with their heart, and should turn again, and I should heal them.” There would appear here to be an indication that the condition of people's hearts is actually intended by God to prevent them from understanding God's words and responding to them. But we must reckon on two things, the prophet's (and God's) irony and his firm belief that God is the prime source of everything.

In His irony God sees the people as being almost afraid of hearing and seeing lest they might have to respond and be healed. And that is because they do not want to respond and be healed. They like being as they are. Certainly they want any benefits that God will dole out to them, but they do not want to be stirred out of their indolent, self-satisfied way of living. Thus they are afraid of hearing and seeing lest their should be changed.

But as one who believes that all that happens is of God Isaiah is also describing what he sees in the light of those terms. He is saying that this is so because although we cannot explain it, God has done it. But it should be noted here that he is not suggesting that God does directly intervene to close men's eyes or to shut their ears, or to darken their understandings. He is simply saying that He allows their natural responses (which are of course the result of His creative work as wrecked by the Fall) to do it for them. He is saying that He refrains from interfering with the natural course of things. These are the people to whom in His sovereignty He has chosen not to make Himself known. But the final fault lies with them and the state of their hearts which they themselves have brought about. For ‘what may be known of God is manifest to them' (Romans 1:19), if only their hearts would respond. Thus they are without excuse. (If we have free will we certainly have nothing to grumble about, and if we did not have freewill we would not be arguing about it).

The close correspondence with LXX that we find here is unusual in Matthew but may have resulted from a Hebrew text which closely paralleled LXX, which he then translates in accordance with his knowledge of LXX, or may even in fact have been taken from LXX itself (but why then do we not find it more often apart from when Mark is being interpreted), or from a list of a series of quotations from LXX. Many Greek speaking Jews in Palestine might well have favoured, and had available in their synagogues, copies of the Septuagint (LXX), which may have been utilised both by Jesus and by Matthew.