John Chrysostom

Then that you may not deem it strange that they believed not, he introduces the prophecy which saith "Hearing ye shall hear and not understand," more now than then: "and ye shall see and not perceive" more now than then. This is not spoken for the former sort, but for the unbelievers. How then? Was it contrary to the prophecy, that those believed? "Go," it says, "unto this people" that is, to the unbelieving people. He did not say this to insult them, but to remove the offence.

Homily on Acts 55 ↗

Theophylact of Ohrid

They did this, he says, people who stopped their ears and closed their eyes, who "will not turn, so that I may heal them." This points to the strong impiety and stubborn aversion of these people. This is said in order to attract and dispose them, and to show that if they turn back, they will be healed. …

Commentary on Acts ↗

Oecumenius

For turning the saying toward a future time, he indicates the reference of the prophecies to later times. Consider, however, the precision regarding the Spirit. He did not say, "And you will not look," but rather, "and seeing you will see and will not perceive." Nor, that you will not hear, but that you will hear and will not understand.

Commentary on Acts ↗