Sermon on John 12:35-43 – “In the Light of Jesus”

Mailed out for: Sunday, May 3rd, 2020 at First Presbyterian Church at Unionville, NY (BPC)

Old Testament reading: Isaiah 53:1-6

[Isa 6:8-13 ESV] 8 And I heard the voice of the Lord saying, “Whom shall I send, and who will go for us?” Then I said, “Here I am! Send me.” 9 And he said, “Go, and say to this people: “‘Keep on hearing, but do not understand; keep on seeing, but do not perceive.’ 10 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.” 11 Then I said, “How long, O Lord?” And he said: “Until cities lie waste without inhabitant, and houses without people, and the land is a desolate waste, 12 and the LORD removes people far away, and the forsaken places are many in the midst of the land. 13 And though a tenth remain in it, it will be burned again, like a terebinth or an oak, whose stump remains when it is felled.” The holy seed is its stump.

New Testament reading:

[1Pe 2:9-10 ESV] 9 But you are a chosen race, a royal priesthood, a holy nation, a people for his own possession, that you may proclaim the excellencies of him who called you out of darkness into his marvelous light. 10 Once you were not a people, but now you are God’s people; once you had not received mercy, but now you have received mercy.

Gospel reading and sermon text:

[Jhn 12:35-43 ESV] 35 So Jesus said to them, “The light is among you for a little while longer. Walk while you have the light, lest darkness overtake you. The one who walks in the darkness does not know where he is going. 36 While you have the light, believe in the light, that you may become sons of light.” When Jesus had said these things, he departed and hid himself from them. 37 Though he had done so many signs before them, they still did not believe in him, 38 so that the word spoken by the prophet Isaiah might be fulfilled: “Lord, who has believed what he heard from us, and to whom has the arm of the Lord been revealed?” 39 Therefore they could not believe. For again Isaiah said, 40 “He has blinded their eyes and hardened their heart, lest they see with their eyes, and understand with their heart, and turn, and I would heal them.” 41 Isaiah said these things because he saw his glory and spoke of him. 42 Nevertheless, many even of the authorities believed in him, but for fear of the Pharisees they did not confess it, so that they would not be put out of the synagogue; 43 for they loved the glory that comes from man more than the glory that comes from God.


We have in this passage that frequent distinction between the light and the darkness. Here particularly we see those who “walk in the light” and “believe in the light” contrasted with those who “could not believe,” those whose eyes are blinded and whose hearts hardened and who have been overtaken by darkness.

As we look at this passage today we’ll look at two commands that God gives to all men, and then we’ll look at the reasons why some do not listen to these commands and do not obey God. It is a terrible for them who are in the darkness, but a great blessing to be “In the Light of Jesus.” And that is the title of the sermon today – “In the Light of Jesus.”

So we find in our text both the command to “walk while you have the light” and the command to “believe the light.” These are the two commands in out text that God gives to all men. And these might even be said to be out of order. That is, in the Christian life, belief is first and then “walking” or “doing good deeds” flows out of the life of the person who believes in Jesus Christ. But here they are mentioned in opposite order perhaps to give emphasis to the first command.

I. Command 1: Walk in the light.

That first command is to “Walk in the light.” In the passage it is actually “Walk while you have the light.”

And this command may be likened to a situation I know many of us find ourselves in each day. If there is something you need at the store or at the post office, for many of us it means being sure to get there while it is still daytime. Yes, the store hours only go so far into the evening, but also there are many who avoid any driving in the dark. It is certainly safer to drive in the light of day than in the dark night. Some years ago after having had LASIK surgery I made all effort to avoid driving in the dark when the streetlights would produce a terrible glare in my eyes nearly making it frustrating difficult for me to focus on the road. And so I had to drive “while it was still light.”

We might think also of ancient times and the dangers that one would risk if they went out in the darkness. They had to accomplish their daily tasks “while it was still light” because thieves and robbers are out at night.

In our text, the command to “walk while you have the light” is the command to not tarry, to not wait, but to come to the Lord, believe in him and walk in his ways.

For the disciples at the time of our passage Jesus was only going to be on the Earth for a short period longer. When Jesus said “walk while you have the light” he was referring not only to that Gospel message which enlightens men, but that he (Jesus) is soon to depart. His hour has now come. The time is short. He says, “The light is among you only a little while longer.” And while the Gospel will never fade away, the time that Jesus has with his disciples is nearing the end.

So this is the first of his two commands: walk in the light. Make haste and do not tarry.

II. Command 2: Believe in the light.

The second of the two commands in our passage is “believe in the light.” To be in the light is to believe in Jesus Christ.

And this command has with it the promise, “that you may become sons of light.” Here we see that right order of things: from belief there follows action. Those who believe are to live as “sons of light.” They will be light as their father is light.

So we have these two commands: believe and walk. Believe in the light and walk in the light. In the light of Jesus.

And these two command really are two sides of the same coin. If you say you believe in Jesus Christ but do not walk in His light, your contention is proven false. And if you mimic the ways of Jesus but have not faith in him you gain nothing, for salvation comes through faith, as the Bible makes clear time and time again.

Application: We are not to mingle with the darkness.

Consider this application: We are not to mingle with the darkness

In a house with a child or children there is likely to be many toys on the floor. And LEGOs seem to have been designed for maximum foot puncture and maximum pain. So a parent, when they awake at night and decide to go to the refrigerator for a late night snack, they must turn on the lights in the rooms through which they walk. And the journey is safe only if the lights are turned on in each room. You cannot skip a single light! If you walk sometimes in the light and sometimes in the darkness you risk stepping on a relocated Christmas tree ornament or attempting late-night backflips courtesy of a stray roller skate.

We should not walk sometimes in the light and sometimes in the darkness.

You do not drive at night with only weak daylights on. Even if other cars happen to see you, you probably won’t see the deer crossing the road. You need not weak lights mixing with the darkness, but powerful lights shinning through the darkness. Turn on the high-beams! Drive in the light.

So too in our lives as Christians. We are to ALWAYS walk in the light. While we know that on this side of glory we will yet continue to sin, God commands us to not sin, but rather to be holy as He is holy. He commands us to be holy ALL OF THE TIME. The one who is holy 99% of the time sinful 1% of the time is a sinful person. The thief, the gambler, the adulterer each sins less than 1% of the time, but they remain thieves, gamblers, and adulterers.

We are commanded to walk in the light. Not some light and some darkness. And we are commanded to walk in the light ALL OF THE TIME.

In this, however, we do fail. And so need the Gospel message.

The Gospel

And this Gospel message is so important because in the command to “walk in the light” we can only see ourselves as failures. We know that we have walked in the light of God. We have sinned. We have fallen short. And, we who are Christians, are grieved over our many sins.

Praise the Lord that his light has come to us and forgiven us of our sins. Not of our own efforts have we been forgiven. Not of our own efforts to do we believe. Not of our own energy do we walk in the light. These are the gifts of God through the work of the Holy Spirit.

I chose our New Testament reading specifically to tie in this Gospel message.

Peter says that we who believe in Jesus Christ are “a chosen race” and have been “called out of darkness into his marvelous light.” And there is no “maybe” about it. Being called into the marvelous light of God we have also the promise that God will never turn that light out on us. He whom God has given the gift of faith will by the Holy Spirit continue to believe and continue in sanctification with the promise of God’s salvation.

God has chosen us, and he has EFFECTIVELY, POSITIVELY, and ASSUREDLY promised that we are called out of darkness and into his marvelous light.

In this we believe, and in the light of Christ we strive to walk. Not that our salvation comes from our walk, but we walk in the light of Jesus in thanksgiving for the salvation promised in him.

But not all walk in the light of Christ. Many walk in darkness. And this is a topic that can be hard to discuss, but it is a topic that we now find in our passage. We find in our passage today the answer to the question “Why don’t all believe?” Why do many walk in the darkness?

III. Why don’t all believe?

That is found in verse 37 through 40:

37 Though he had done so many signs before them, they still did not believe in him, 38 so that the word spoken by the prophet Isaiah might be fulfilled: “Lord, who has believed what he heard from us, and to whom has the arm of the Lord been revealed?” 39 Therefore they could not believe. For again Isaiah said, 40 “He has blinded their eyes and hardened their heart, lest they see with their eyes, and understand with their heart, and turn, and I would heal them.”

There is then at least three reasons why many do not believe.

A. So that the prophecy of Isaiah would be fulfilled.

One reason why people do not believe in Jesus is so that the prophecy of Isaiah would be fulfilled. It was prophesied that there would be people who ‘Keep on hearing, but do not understand; keep on seeing, but do not perceive.’ So God’s Word needed to be fulfilled. That applies most of all to that current situation that Jesus was in. People then in his own time rejected him. Surely there are many who reject him also today, but the primary focus is the rejection there in Jesus’ own time.

Now, one thing important about this reference to the prophet Isaiah is that the Apostle John specifically identifies this prophecy as coming from Isaiah. Of course, you and I don’t doubt that. We find the prophecy in the book of Isaiah. But the non-believing Liberal scholars have been making various claims for a couple centuries now that the book of Isaiah was written by more than 1 author. They might have Isaiah himself writing the first part, but then they claim the later chapters were written by someone else at at later time. Well, John the Apostle doesn’t think so! The very verse he quotes is from those later chapters in Isaiah! And he calls it Isaiah!

But moving on, we want to know WHY it is that many do not believe in Jesus. Yes, it is to fulfill the prophecy, but ultimately, as the text tells us, it is because “they could not believe.” That is the second reason many do not believe: they could not believe.

B. “They COULD NOT believe.”

The one who walks in darkness simply does not have the ability to believe. His will is not free to believe; his will is in bondage to sin. The light has not come to him. The light has shined all around him indeed, but it has not penetrated his heart inwardly. Only those whom the Lord savingly and irresistibly sends the Holy Spirit will believe. All other CAN NOT believe. Belief in Jesus requires the Holy Spirit, and those who do not believe do not have the Holy Spirit. Thus they cannot believe.

C. The heart of the unbeliever is hardened by themselves and by God.

Then, third, many do not believe because the heart of the unbeliever is hardened by themselves and by God. This can be very difficult to understand. The heart of the unbeliever is hardened by themselves and by God. It is not 50-50. It is not 50% hardened by man and 50% hardened by God. The unbeliever’s heart is hardened 100% by himself and 100% by God, but in different ways or different levels.

In the Scriptures we see both man hardening his own heart, and God hardening the hearts of men. And in fact, it is far more common in Scripture to find that the hardening is the action of God, not man. From my search is was something like 80% of the references are to God’s hardening, and only 20% to man’s hardening.

First man hardening his own heart:

[Exo 8:15 ESV] 15 But when Pharaoh saw that there was a respite, he hardened his heart and would not listen to them, as the LORD had said.

[Exo 8:32 ESV] 32 But Pharaoh hardened his heart this time also, and did not let the people go.

Then God hardening the hearts of men:

[Exo 4:21 ESV] 21 And the LORD said to Moses, “When you go back to Egypt, see that you do before Pharaoh all the miracles that I have put in your power. But I will harden his heart, so that he will not let the people go.

[Deu 2:30 ESV] 30 But Sihon the king of Heshbon would not let us pass by him, for the LORD your God hardened his spirit and made his heart obstinate, that he might give him into your hand, as he is this day.

[Jos 11:20 ESV] 20 For it was the LORD’s doing to harden their hearts that they should come against Israel in battle, in order that they should be devoted to destruction and should receive no mercy but be destroyed, just as the LORD commanded Moses.

There are then two errors that could be made here. The first is incredibly rare, the second is quite common. But they are equally erroneous.

First, there is the error of calling God the author of evil. Our confession teaches against this. God is not responsible for the sins of man. The sins of man are man’s sins, not God’s. And man is responsible to the holy God for his sin. God can rightfully and justly punish sin. God is not to be blamed for the sin of man.

The second error is to deny the sovereignty of God and ignore his active hardening influence on unbelievers, especially notable in the case of Pharaoh. This error is far too common, even among many who would say they are Calvinists.

Calvin, in many places, makes it clear that God’s action of hardening the hearts of certain men is active, not passive. In one such place Calvin says:

“God is very often said to blind and harden the reprobate, to turn their hearts, to incline and impel them, as I have elsewhere fully explained (Book 1 c. 18). The extent of this agency can never be explained by having recourse to prescience or permission.”

And in another place:

“How foolish and frail is the support of divine justice afforded by the suggestion that evils come to be not by His will, but merely by His permission. … Again it is quite clear from the evidence of Scripture that God works in the hearts of men to incline their wills just as He will, whether to good for His mercy’s sake or to evil according to their merits.”

We must not deny God’s sovereignty. He is in control of all things. And as our confession says, not by “bare permission” but rather God ordains all things.

So we see this in our passage: “HE [God] has blinded their eyes and hardened their heart, lest they see with their eyes, and understand with their heart, and turn, and I would heal them.” HE has done so. That is, God has.

The error of denying God’s sovereignty is the error of saying he is NOT the cause of the hardening of man’s heart. And the error of calling God the author evil is the error of saying he is the ONLY cause of the hardening of man’s heart.

But the unbeliever’s heart is hardened both of his own doing and, as Calvin affirms, by the will of God.

This can be quite challenging to understand, I admit. I hope do have done justice to explaining it. Before I conclude, I’ll give a second explanation that might help:

The fact that both man AND God are said to “harden the heart” is best understood, I believe, by the use of a distinction between the “proximate cause” and “ultimate cause.” God is the ultimate cause of all things. But man is the one who actually carries out his own sin. Man is the proximate cause of sinning and of hardening his own heart, because the action was actually carried out by man even if God has purposed such to occur.


So let us summarize. By the work of the Holy Spirit believers are given the light of faith that they may walk in the light. But unbelievers cannot believe because they do not have that light and in fact have hardened their hearts in opposition to God as He has ordained.

Without the Light of Christ, there is darkness. And only the spirit of God can break through that darkness.

In the gospel we have the light that breaks through the darkness and changes the heart of stone into a heart of flesh. The hardened stone heart cannot believe, but the heart of flesh knows salvation in the light of Jesus.

Praise the Lord that He has brought to us the Light of Jesus Christ so that we might believe in him and follow him as Children of light. Amen.