We are continuing our journey through the Sermon on the Mount, but this isn’t a verse-by-verse study. Week by week, we are tracing the places where Jesus' teaching runs head-on into the values of the world around us… Places where faith and culture collide. This is week three of our series, COLLIDE: prepare for impact, and today we face one of the biggest collisions of all: the collision over truth.

So far, we have talked about this tension in the world: the impact of being salt and light and of facing difficult conversations. We have also talked about marriage and, consequently, anger, lust, and divorce. It has gotten a little tough, not because Jesus is harsh, but because he goes after the heart every time. You see, we tend to treat sin as a behavior problem, something you fix by trying harder, but Jesus treats it as a heart problem. What we do matters, but why we do it matters even more.

Last week we left off with heart-level teaching on marriage, and Jesus has some hard words about divorce. He said it was never God’s ideal but a concession he made because men were abusing their power, discarding their wives without provision or protection. And so, Jesus doesn’t affirm that system but looks back to God’s original design in the garden for one man and one woman united for life, and says,

“What God has joined together, let man not separate” (Matthew 19:6).

And we learned that your past does not get the final word on who you are. Whatever happened, whatever was said or done, and whatever you carry from those years do not define you, and they don’t have to follow you into your future. Your failures may be part of your story, but they are not the end of it. When you belong to Jesus, he is the one who names you, and he calls you forgiven, redeemed, and a new creation.

With that introduction, we are set for the next collision Jesus names: truth. A church without truth cannot survive. A friendship without truth cannot survive. A walk with God without truth cannot survive. Every relationship in your life is only as strong as the reliability of the words spoken within it.

This is one of the sharpest collisions in our entire series because our culture has quietly redefined what truth is. We used to argue about what was true. But now we are told there is no single truth, only your truth and my truth. In our culture today, each of us is free to build our own version of reality and call it valid.

You don’t have to look far to see it. Turn on any two news channels covering the same overseas event, such as the war involving Iran and Israel, and you won’t just hear two different opinions. You will hear two entirely different sets of facts, each accusing the other of propaganda. Whole movements now insist that truth is simply whoever holds the most power, so what is called unjust today can be called righteousness tomorrow, because there is no fixed standard to rely on.

That sounds tolerant on the surface, but if you live in it for very long, you will find it exhausting. If truth is whatever each person decides for themselves, then no promise, no contract, and no marriage covenant can be trusted to hold.

But Jesus doesn’t let us live in that fog. Truth is not a feeling you construct or fabricate, nor is it whoever shouts loudest. Truth is not a concept to be debated; it is a person to be known.

To see how far we have drifted as a culture, we will trace this from the command God gave to a prophet who confronted his people and then bring it home with Jesus.

Long before Jesus stood on that hillside and preached this message, God had already told his people exactly how he felt about truth. It was one of the 10 Commandments, spoken at Mount Sinai and etched in stone.

"You shall not give false testimony against your neighbor" (Exodus 20:16).

I want you to notice how specific this is. God didn’t just say to be an honest person in general, but he named the exact way truth gets weaponized: words used against your neighbor for your own advantage. You see, lying was never just a private failure between you and your conscience. It is a double-edged sword, an offense against your neighbor and against the God who made you both.

Over time, this command got narrowed. In the centuries leading up to the coming of Jesus, religious teachers turned it into a technical rulebook about which oaths were legally binding and which ones you could quietly wiggle out of. So if you hadn’t sworn the exact right oath in the exact right way, you could tell yourself you hadn’t really broken your word. What began as a command to protect your neighbor had shrunk into a courtroom loophole.

Centuries after giving the law on Mount Sinai, God sent prophets to call His drifting people back. The prophet Zechariah delivered this word from the Lord:

"These are the things you are to do: Speak the truth to each other, and render true and sound judgment in your courts" (Zechariah 8:16).

Zechariah extends the command beyond ordinary, everyday conversations to the courtroom because God’s people had learned to protect themselves with careful, technically true language while still deceiving one another. The prophet called them back to something simple yet costly: speak the truth to one another, not just the truth you can get away with.

Then Jesus steps in, the Word who was in the beginning, the Word who was with God, the Word who was God, the Word who became flesh and made His dwelling among us (John 1:1, 14). And the very One who spoke the commandment at Sinai and sent the prophet to call His people back now takes those same words and goes further than either one ever did.

He says, "Again, you have heard that it was said to the people long ago, 'Do not break your oath, but keep the oaths you have made to the Lord'" (Matthew 5:33).

In other words, when Jesus spoke these words, the loophole Zechariah confronted was still in full force. People had built a whole system of oaths, some binding, some not, depending on what you swore by. Jesus says,

"But I tell you, Do not swear at all: either by heaven, for it is God's throne" (Matthew 5:34).

Because you may wiggle out of it later, there will be no accountability. He continues to say,

"Or by the earth, for it is his footstool; or by Jerusalem, for it is the city of the Great King" (Matthew 5:35).

Jesus wisely dismantles the entire system in one move. Don’t swear by heaven because it is God’s throne, by earth because it is his footstool, or by Jerusalem because it is his city. Each of those carried great weight and was a way to sound trustworthy while quietly leaving yourself an exit.

"And do not swear by your head,” Jesus says, “for you cannot make even one hair white or black" (Matthew 5:36).

Each of those oaths borrowed authority that belongs to God alone. And so, a follower of Jesus does not need to swear by anything to be believed. There shouldn’t be any need for extra promises, no big speeches, no “I swear on a stack of Bibles.” Your character should be enough to back up your word.

"Simply let your 'Yes' be 'Yes,' and your 'No,' 'No'" (Matthew 5:37).

In other words, when you feel the need to add something extra just to be believed, it chips away at your character and your witness as a follower of Jesus. You don't need to swear by anything or dress up your words to make them sound more trustworthy; a simple yes or no should be enough, because your life backs up what you say.

Jesus says, “Anything beyond this comes from the evil one” (Matthew 5:37).

Now, it is easy to assume this is aimed at someone else, like a politician who distorts the facts or a tax collector who skims a little off the top, but Jesus is speaking to ordinary Jewish believers who have grown comfortable with small, socially acceptable forms of dishonesty.

In other words, he is speaking to ordinary people like you and me, those who have made a promise to God and quietly set it aside, where it has been forgotten, like that New Year’s resolution from last January. Remember how you said you were going to read through the entire Bible this year? We have all broken promises to the people around us, to ourselves, and to God himself. That is exactly the soil in which this teaching grows and where it gets personal.

This command, this expectation of honesty and truthfulness, is a thread that runs throughout Scripture. In fact, the early church received the same charge in almost the same words. The apostle Paul offers one more reason to take it seriously.

"Each of you must put off falsehood and speak truthfully to his neighbor, for we are all members of one body" (Ephesians 4:25).

In other words, he says, as members of one body, when you lie to a brother or sister in Christ, you are working against your own body, like a hand fighting against an arm. And Paul says,

“If one part suffers, every part suffers with it” (1 Corinthians 12:26).

Think about how easily we drift from the truth in everyday life. “I’ll be home by 10” becomes 10:30, with no phone call or apology. “I’ve got it handled” becomes a bill that goes unpaid for months. “I’m fine” becomes three weeks of silent treatment and bitterness.

Now, I know that none of that is courtroom perjury, but every example is a small crack in the same foundation: the simple ability to trust that your yes means yes. You see, you don’t need a dramatic betrayal to destroy trust. You simply wear it down one broken promise at a time.

It shows up at work when you stretch the truth a little to make the sale, round up the timesheet in your favor, or give your boss an excuse that isn’t quite accurate.

It shows up at school when you tell your teacher the dog ate your homework, copy a friend’s answers and call them your own, or say you studied when you really didn’t.

It shows up at home with our kids when we promise a consequence we never intend to carry out.

Today, it is in those little compromises that Jesus wants to do his deepest work. As followers of Jesus, our words should be so reliable that swearing an oath to back them up would almost be an insult to the one we follow. When you feel the need to swear on God’s name or your mother’s grave just to be believed, you are quietly admitting how unreliable your yes has become.

The bottom line is that Scripture doesn’t treat this as a minor character flaw. When John describes his vision of the final judgment, he includes this sobering list:

“The cowardly, the unbelieving, the vile, the murderers, the sexually immoral, those who practice magic arts, the idolaters and all liars—their place will be in the fiery lake of burning sulfur" (Revelation 21:8).

In other words, God places lying in the same category as murder and idolatry because, at its root, a lie is a deception. It is an attempt to reshape reality to suit ourselves rather than submit to the God who defines what is real.

Now, if that verse makes you uncomfortable, it should, because none of us are innocent under that list. That’s exactly why we need more than a warning; we need a way out. And God gave us a way out, because truth is not just a standard for measuring our words. Truth has a name, and his name is Jesus.

Our culture tells us truth is a moving target, but Jesus says something far more solid. He says,

"I am the way and the truth and the life. No one comes to the Father except through me" (John 14:6).

That means that every time you bend the truth, exaggerating to make something sound better or leaving out an important detail, or every time you break a promise or use words to manipulate instead of reveal, you are not just breaking a rule. You are moving away from a person.

This whole series has followed one pattern. Jesus told us,

“Unless your righteousness surpasses that of the Pharisees and the teachers of the law" (Matthew 5:20).

Then He tore down every hiding place we have built to cover our anger, our lust, and our broken vows. And He says something that should stop us in our tracks:

"Be perfect, therefore, as your heavenly Father is perfect" (Matthew 5:48).

And we all say, "I'm not perfect." And that is good because that’s exactly the posture Jesus is looking for. When you stand humbly before Him and say, "I can't do this. I need You to save me," He says, “Trust me. Receive the life I offered for you.”

He lived the perfect life we couldn’t live. He died in our place. He himself bore our sins in his body on the tree so that we might die to sins and live for righteousness (1 Peter 2:24).

That’s why, even though we have sinned and fallen short again and again, Scripture can still say,

"This is love: not that we loved God, but that he loved us and sent his Son as an atoning sacrifice for our sins" (1 John 4:10).

In other words, his death satisfied God’s justice on our behalf because the Bible promises that everyone who trusts him receives the right to become a child of God. That faith is credited to us as righteousness, so that in him we might become the righteousness of God (2 Corinthians 5:21).

I'm so thankful that forgiveness is a gift, because we could never earn it by keeping our promises. We could never be good enough, and that's exactly why we need a Savior, not just a standard. But Jesus didn't leave us to figure it out on our own. He sent the Holy Spirit, whom He called the Spirit of truth, to guide us into all truth (John 16:13). That same Spirit who fell on the believers at Pentecost lives in every believer today, empowering us to be people whose words can be trusted, not by our own willpower, but by His power working in us.

And so, this message isn’t simply about right and wrong, truth or falsehood, but about life and death. It’s just as Jesus said,

"The thief comes only to steal and kill and destroy" (John 10:10).

And the enemy is happy to lead you down a road that feels harmless. When it comes to anger, he whispers, “It’s not your fault.” When it comes to lust, he whispers, “It doesn’t hurt to look.” When it comes to your word, he whispers, “Everybody stretches the truth a little.”

But our Lord is the good Shepherd, and his voice sounds nothing like that whisper. He said,

"My sheep listen to my voice; I know them, and they follow me" (John 10:27).

In other words, every time we hear his voice or read his Word and take a step of obedience, we are walking toward the abundant life Jesus offers us. In contrast to the intentions of our spiritual enemy, Jesus said,

"I have come that they may have life, and have it to the full" (John 10:10).

And so, as we sat on that Galilean hillside, joining the crowd listening to his teaching, if you feel beat up right now, I want you to understand that was never the point.

You see, the Bible says, "The law was added so that the trespass might increase. But where sin increased, grace increased all the more" (Romans 5:20).

If you feel the Holy Spirit’s conviction, it is a caring embrace, an invitation to run toward him, and not away from him.

As you have listened today, maybe a specific broken promise comes to mind. A vow at the altar you have not fulfilled the way you meant to. A word to a friend you never followed through on. A promise to God that quietly faded.

I want to encourage you today not to spend another moment defending yourself or explaining why it doesn’t count, but to bring it to Jesus exactly as it is. He isn’t watching and counting your broken promises. He has taken them and nailed them to his cross, and he is waiting to hand you his perfect record instead. That is why the Bible tells us

"There is now no condemnation for those who are in Christ Jesus" (Romans 8:1).

From the cross, Jesus declared that the price for our sin had been paid in full. He said, “It is finished,” yet the devil wants you to spend your life in fear, replaying what you did and trying to justify yourself. But you can’t do that, and you don’t have to, because only Jesus can justify you before the Father, and he already has because of what he did on the cross. When we understand how much he loves us, that love compels us to no longer live for ourselves but for him who died for us and was raised again (2 Corinthians 5:14-15). Not because we have to, but because we want to, knowing his ways are better than ours.

You see, God has already taken care of our sin problem; he has given us a way out, and he has already paid the price. Every lie we have told, every vow we let slide, every yes that turned out to be a no, all of that was laid on Jesus. He was the one Scripture says,

God sent his son Jesus to take our punishment, to be our substitute, because he is the only man who…

"He committed no sin, and no deceit was found in his mouth" (1 Peter 2:22).

And so, he stood silent before his accusers and took what we deserved.

"When they hurled their insults at him, he did not retaliate; when he suffered, he made no threats. Instead, he entrusted himself to him who judges justly" (1 Peter 2:23).

So that we could be lifted up and live in him. Don’t miss the power of what Isaiah says about our Savior.

"He was pierced for our transgressions… crushed for our iniquities; the punishment that brought us peace was upon him, and by his wounds we are healed" (Isaiah 53:5).

In other words, his wounds bring more than forgiveness. They bring peace to a guilty conscience and healing to broken hearts, broken bodies, and broken relationships. Jesus came to make whole everything sin has fractured.

And here is the good news for everyone who has ever been let down by someone’s word, including your own. Jesus has never broken his word or lied, and every promise God has ever made finds its answer in him.

"For no matter how many promises God has made, they are 'Yes' in Christ" (2 Corinthians 1:20).

When He said he would forgive you, he meant it. When He said he would never leave you or forsake you, he meant it. When He promised to pour out His Holy Spirit on all who call on him, he meant it. And that promise is still for you today. You can build your whole life on His Word, because Jesus is the one person whose yes has never failed to mean yes.

Graphics, notes, and commentary from LifeChurch, Ministry Pass, PC Study Bible, Preaching Library, and Sermon Central. Scripture from the New International Version unless otherwise noted.