Christian Application of Isa 6:9-13
For many Christians, and readers of the New Testament, verses 9-13 (esp. vv. 9-10) are familiar from their use in the Gospels and by the early Christian missionaries (such as Paul). This provides an interesting example of how Old Testament passages can be taken out of their original context, and applied to a new setting and situation. For commentators who wish to affirm both a single (primarily/original) meaning to the Old Testament prophecies, and the inspiration of the New Testament authors/speakers, it is necessary to posit something like an “inspired application”, which, though secondary, carries its own inspired meaning and truth.
Jesus himself made use of vv. 9-10, citing them, according to the Synoptic tradition, as part of an explanation for why he taught and preached using parables. We tend to think of the parables as illustrations which help the average person to understand what Jesus is saying; however, according to Mark 4:10-12 par, Jesus’ intention is the opposite. He is communicating the “secret” of the Kingdom of God, but this “secret” is being revealed only to his close followers. For others, the truth of the Kingdom remains hidden, and parables serve to conceal the truth from the people at large. It is in this context that Isa 6:9-10 is cited. The Greek wording (in Mark) differs from both the Hebrew MT and the Greek LXX, especially in its use of the verb a)fi/hmi (“release, let [go] from”), with its connotation of forgiveness from sin: “…so they should not (at any time) turn back and it be released for them” (the parallel in Matt 13:14-15 is closer to the LXX). If forgiveness from sin is meant here, then it gives to vv. 9-10 an application toward the idea of eternal salvation that is rather troubling, in light of God’s active role (in the original prophetic message) in keeping people from recognizing the truth.
The Gospel of John does seem to take things a step further, in this direction, when the author (and/or his underlying tradition) cites vv. 9-10 in 12:39-41, using the prophecy as a way of explaining why many Jews at the time were not able to trust in Jesus. In the Johannine writings, the verb pisteu/w (“trust”) tends to be used in the specific sense of the trust in Jesus (as the Messiah and Son of God) that marks the true believer, and one who possesses eternal life. Thus, to say that these people were not able to trust means that they were not (and could not be) true believers destined for salvation and eternal life.
In the closing scene in the book of Acts (28:23-28), as Paul speaks with Jews in Rome, he also cites Isa 6:9-10 (vv. 26-27), similarly, as an explanation for why many of these Jews were unable/unwilling to believe (lit. were “without trust”, v. 24f). The closing words in v. 28, pitting the trusting Gentiles against unbelieving Jews, may seem disturbing to our modern-day sensibilities, but they reflect the historical situation faced by Paul and other missionaries at the time. He deals with the Jew/Gentile problem—i.e. why many Gentiles trust in Jesus while many Jews do not—more comprehensively in his letter to the Romans (esp. chapters 9-11).
What is common in all these passages, in relation to Isa 6:9-13, is the idea that God is specifically acting so that many people do not (and cannot) see or recognize the truth. This seems to go squarely against how we tend to think about God—that he wants everyone to understand and accept the truth, and any failure to do so is our responsibility, not God’s. In balancing the sense of the control human beings have over their own destinies, with the extent to which they are controlled by God (or the deities, in a polytheistic setting), the ancient peoples tended to emphasize God’s ultimate (and sovereign) control, whereas modern (Western) society, by contrast, stresses individual human control and responsibility.
Why does God not want His people to see/understand the truth and turn back to Him (in repentance, etc)? To answer this, we must keep close to the original historical context of Isa 6:9-13. Isaiah’s mission in chap. 6ff is to announce the judgment that is coming on the people of Israel and Judah, in the form, primarily, of the Assyrian military invasion(s). If the people realized the nature of this judgment, and its imminence, they might well repent, and this would prompt YHWH to curtail the just punishment that the people deserved for their sins and crimes. Instead, in order for the full punishment to be meted out, and for the judgment to be realized in full, the people are prevented from realizing (or accepting) what is happening to them, until it is too late.
This is comparable in some ways to the hardening of Pharaoh’s heart in the Exodus narratives. By hardening Pharaoh’s heart (Exod 4:21; 7:3; 9:12; 10:1, 20, 27; 11:10; 14:4, 8, 17), God brings about the full punishment upon Egypt, the completion of all the “plagues”, including the last and greatest (death of the firstborn). This, of course, does not remove the guilt or responsibility of Pharaoh—there is a sense in which he hardens his own heart (Exod 8:11, 28; 9:34; cf. also 7:13-14; 8:15; 9:7, 35; Roberts, p. 102 note)—but ultimately it is God (YHWH) who brings this about. The point is that God’s action (here through the prophet Isaiah) allows for the full judgment/punishment of the people to be realized. Only after this punishment has taken effect—through conquest, destruction, and exile—can the restoration of the people occur (v. 13).
References above marked “Roberts” are to J. J. M. Roberts, First Isaiah, Hermeneia Commentary series (Fortress Press: 2015).