How do we think about the purpose of evangelism? Does the proper, faithful sharing of God’s Word ever result in a person’s turning away from God?

The calling of the prophet Isaiah, recounted in Isaiah 6, suggests that it does.

I teach the book of Isaiah as part of a seminary course on the Prophets, and I can count on the eighth-century prophet to challenge my students’ beliefs, many of which they may not even realize that they hold.

Take, for instance, the call of Isaiah in the sixth chapter. In this well-known passage, the Lord appears to Isaiah as he is praying in the temple in Jerusalem. His prayers are disrupted when the temple environment gives way to a vision of the heavenly throne room, and the Lord appears from the throne to commission Isaiah for his prophetic ministry. The imagery of the passage is vivid and thrilling: divine glory and regalia, the seraphim singing in what seems to be antiphonal style, and the coal from the altar touched to the lips of the preacher. All of this heavenly wonderment might draw our attention away from the actual message that Isaiah is called to preach.

What is often forgotten about Isaiah’s call is the actual purpose of the message that he is to proclaim to the people of Judah and Jerusalem. In Isaiah 9:6, we come to the matter:

And [the Lord] said, “Go, and say to this people:

“‘Keep on hearing, but do not understand;
keep on seeing, but do not perceive.’
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.” (Isa. 6:9–10)

If there were an ancient Near Eastern equivalent to a “record scratch,” this would be the time to cue it up. Isaiah’s calling is to preach a prophetic message that will not be received by the people to whom he is sent. On top of that, the purpose of the prophetic message is actually to harden the people against the words of God, to hinder their turning back (i.e., repenting) to the Lord so that the impending judgment might be avoided, or at least lessened.

We might think that we have misread the purpose of the call, but the prophet himself seems to understand it completely. His first question, “How long, O Lord?” (v. 11), indicates as much. If the Lord has plans to discipline His people, then surely such plans have a terminus.

This was not the first time that the Lord had commissioned a message that would be met with resistance and would even expedite a hardening of the human heart. Moses was told ahead of time that Pharaoh would be hardened so that the Lord’s redemptive power might be fully on display (Ex. 7:3–4). There is also the difficult, and somewhat humorous, passage involving a deceptive spirit that was sent out by the Lord in order drive apostate King Ahab to his death by sending him to battle against the Arameans (1 Kings 22:1–28). After Isaiah, a similar issue arose when Jesus’ Apostles questioned Him about His use of parables. He explicitly said that a parable teaches truth while also shrouding it from the unbeliever. Interestingly, Jesus cited Isaiah’s calling as a precedent for this sort of prophetic method (Matt. 13:10–17).

We should not be surprised when souls are saved as result of the worst, most mealy-mouthed, ham-fisted presentation of God’s Word.

So, how do we understand the power of God’s Word to harden the human heart?

First, we must understand that God’s Word is actually performative in the literal sense. He speaks and His speech changes the world. He speaks creation into existence (Gen. 1). This word is closely identified with creation as well as the second person of the Trinity in John 1, and when followers of Christ give expression to the Word in their own lives through the power of the Spirit, they are giving expression to Christ Himself (John 15:26; 1 Cor. 2:2; Heb. 1:1–2; 1 John 4:2–3). Isaiah himself sums up the power of the divine word, saying that when the word of God Almighty is unleashed in the world, it always has its intended effect and never returns void (Isa. 55:11).

So, we should not be surprised to find that the creative, personal, and powerful words of the Lord will repel those whose hearts have not received new life in the Spirit. There are those who, due to their rebellious and destructive desires, have no interest in God’s Word. Indeed, they are even repulsed by the call to repentance. For them, God’s Word is presumed to be, at worst, hateful and immoral, and, at best, laughable and naive. The Apostle Paul argues that the surface response suggests a deeper and more traumatic reaction to the power and person of Christ.

But thanks be to God, who in Christ always leads us in triumphal procession, and through us spreads the fragrance of the knowledge of him everywhere. For we are the aroma of Christ to God among those who are being saved and among those who are perishing, to one a fragrance from death to death, to the other a fragrance from life to life. (2 Cor. 2:14–16)

In other words, when God’s Word is faithfully communicated, it will have the double effect of drawing the elect to Him and driving the nonelect away. All preaching of God’s Word runs the risk of both outcomes, no matter how eloquent or contextualized the communication. Note that the nonelect will be driven away by the preached Word of God even if the preacher is none other than Jesus Himself (John 6:66).

This, of course, does not mean that the Christian may communicate the Word of God in any way that is less than clear, faithful, and contextualized. The Christian must endeavor to remove any obstacle to proper understanding. Throughout their ministries, Jesus and the Apostles model for us effective and intelligible communication.

We should not be surprised, however, when souls are saved as result of the worst, most mealy-mouthed, ham-fisted presentation of God’s Word. It will happen, and it will be wonderful.

We should also not be shocked to learn that, as for Isaiah, there may be times when our faithful expression of the gospel does not lead a person to salvation but rather confirms for them what they have already convinced themselves was true of the Christian faith. Tragically for Jerusalem in Isaiah’s day, the spiritual life of the population had shifted to one of mass, abject unbelief (Isa. 1:2–4). Isaiah’s message would serve only to harden them further, driving them toward discipline.

There are those in our lives who will never worship Jesus because their hearts are hardened to and by the gospel. Those cases are tragic.

But there are those who will come to faith no matter how faulty or how unworthy our Christian witness is. Those cases make the angels sing.

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