Although Jesus was not the first to use parables in his teaching, his extensive use of them was a distinct feature of his teaching style. But why? Some suggest that he simply harnessed the power of story to enhance his teaching. But Jesus himself explains why he used parables, and he grounds his explanation in a network of Old Testament texts, with Isaiah 6:9–10 as the star of the show.

Grasping Jesus’s purpose provides valuable lessons for our understanding and proclamation of the gospel.

Lest They Turn

Jesus’s explanation for why he teaches in parables is embedded within the parable of the sower and soils. (Although this parable is recorded in all three Synoptic Gospels, we will focus on Matthew’s version.)

The parable comes at the beginning of an extended section of parables focused on the nature of God’s kingdom (Matthew 13:1–52). After Jesus tells the crowd the parable of the sower (Matthew 13:1–9), the disciples ask him privately why he speaks to the crowds in parables (Matthew 13:10). Jesus responds by highlighting their privileged position as disciples: God has chosen to reveal the secrets of the kingdom to them (Matthew 13:11–12, alluding to “mystery” language used in Daniel). He then directly answers their question:

This is why I speak to them in parables, because seeing they do not see, and hearing they do not hear, nor do they understand. Indeed, in their case the prophecy of Isaiah is fulfilled that says: “You will indeed hear but never understand, and you will indeed see but never perceive.” For this people’s heart has grown dull, and with their ears they can barely hear, and their eyes they have closed, lest they should see with their eyes and hear with their ears and understand with their heart and turn, and I would heal them. (Matthew 13:13–15, citing Isaiah 6:9–10)

Jesus’s statement that he teaches in parables alludes to Psalm 78:2 (which Matthew cites explicitly in Matthew 13:35), but the sensory malfunction language (ears that do not hear, eyes that do not see, hearts and minds that are dull) anticipates the quote from Isaiah 6:9–10. Why does Jesus turn here to explain his purpose to the disciples?

Unseeing Eyes, Unhearing Ears

In its original context, Isaiah 6:9–10 is part of God’s commission to Isaiah as a prophet. In response to seeing Yahweh exalted on his throne, Isaiah responds to Yahweh’s question, “Whom shall I send, and who will go for us?” with an emphatic, “Here I am! Send me” (Isaiah 6:1–8). Verses 9–10 then give the content of Isaiah’s message to rebellious Israel. God commissions him to denounce their spiritual deafness, blindness, and hardness of heart — the realities that keep Israel from responding to God’s call to repentance and restoration.

This was not a new response for Israel. It had been this way since Moses’s day, who used similar sensory malfunction language to describe Israel (Deuteronomy 29:2–4). Elsewhere, Scripture connects this sensory malfunction language to the effects of idolatry. Those who worship idols become like them, having eyes that cannot see, ears that cannot hear, and hearts that do not understand (Isaiah 44:9–20; Psalm 115:3–8).

“The parables are more like thermometers than thermostats; they reveal a person’s spiritual condition.”

But when Jesus cites Isaiah 6:9–10 and applies it to the listening crowds, he is doing more than simply identifying a recurring pattern in redemptive history. Notice that Jesus introduces the words of Isaiah 6:9–10 by saying, “Indeed, in their case the prophecy of Isaiah is fulfilled” (Matthew 13:14). The sensory malfunction and hardness of heart directed toward Jesus is the culmination of that pattern. The climactic nature of God’s revelation of himself in Jesus leads to a heightened level of sensory malfunction and hardness of heart that fills up the significance of previous occurrences of this pattern.

Wrapping Pearls in Parables

Jesus teaches in parables in order to expose a person’s spiritual condition. The parables are more like thermometers than thermostats; they reveal a person’s spiritual condition more than they determine it. That is why Jesus repeatedly says, “He who has ears to hear, let him hear” (Matthew 11:15; 13:9, 43). Those who have been made spiritually alive and are now able to hear the voice of the Son of God (John 5:25–26) must respond by obeying Jesus’s word. They must be not merely hearers of the word, but doers (James 1:22).

By contrast, the parables further harden those whose spiritual eyes, ears, hearts, and minds have malfunctioned because of their idolatrous rebellion against God. “For those without ears to hear, parables seem to conceal more than they reveal, so that superficial hearing and seeing do not lead to true spiritual understanding or perception,” Craig Blomberg writes (Commentary on the New Testament Use of the Old Testament, 46). The parables are thus a way of speaking the good news of the kingdom to the crowds while at the same time not casting pearls before swine (Matthew 7:6). As D.A. Carson puts it, Jesus teaches in parables “in such a way as to harden and reject those who are hard of heart and to enlighten — often with further explanation — his disciples” (Matthew, 309).

John also uses Isaiah to explain the people’s rejection of Jesus (John 12:36–43). Despite all the signs Jesus did, they did not — in fact, could not — believe in him, which fulfilled the words of Isaiah 53:1. Indeed, the reason they could not believe in him is explained by a citation of Isaiah 6:9–10. After quoting the prophet, John explains that “Isaiah said these things because he saw his [Jesus’s] glory and spoke of him” (John 12:41). In other words, the exalted Lord whom Isaiah saw sitting on the throne of heaven was none other than Christ himself (Isaiah 6:1–5). Thus, Isaiah foretold the rejection of Jesus nearly seven hundred years before he was born.

Simply put, Jesus teaches in parables to demonstrate the need for divine revelation to understand the mysteries of the kingdom and to reveal the spiritual condition of his listeners. Both of these realities are grounded in his understanding of Isaiah 6:9–10.

Eye-Opening God

The way that Jesus and the New Testament authors use Isaiah 6:9–10 teaches us at least three important lessons.

First, the gospel was hidden in plain sight in the Old Testament but is now revealed through the person and work of Jesus Christ. On the one hand, the New Testament makes it clear that the good news of Jesus Christ is the fulfillment of the Old Testament hope. At the same time, the way that Christ fulfills the Old Testament hope is unexpected in many respects.

Second, God must open a person’s spiritual senses to rightly perceive the gospel. By fallen nature, we come into this world as spiritually dead sinners with hearts of stone (Ephesians 2:1–3; Ezekiel 36:26). Apart from God’s Spirit making us spiritually alive (Ephesians 2:4–6), giving us eyes to see (2 Corinthians 4:6) and hearts that are responsive to God (Ezekiel 36:26–27), no one ever comes to faith in Christ. If we trust in Jesus, our hearts should be filled with gratitude that God has opened our eyes to see the beauty of Christ, because none of us deserves such a privilege. There is no room for arrogance in the kingdom. No one comes to know Christ because he is smarter or wiser than others. As believers, we should marvel at the fact that God has opened our eyes to see “the light of the knowledge of the glory of God in the face of Jesus Christ” (2 Corinthians 4:6).

Finally, truly understanding these realities will make us people of prayer. All our efforts to share the gospel with others should be bathed in prayer. Learning how to respond to common questions about Jesus, the Bible, and Christianity is wise, but our ability to explain and defend the gospel is not what enables people to repent and believe in Jesus. This truth frees us from the anxiety that comes from thinking a person’s response to the gospel depends on how well we communicate.

Instead, we can confidently pray for God to do what only he can do. We can pray that, as he did with Lydia (Acts 16:14–15), God would open our hearers’ eyes to see the beauty of Christ, open their ears to hear the good news, and replace their heart of stone with a heart of flesh that responds to God in faith and obedience.