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.