[INTRO]

My five-year-old was playing checkers on the tablet last week during skating lessons. She dragged a piece to a square it couldn’t reach. Nothing happened. She had a jump available and didn’t take it. The app forced her hand. It even forced me to win when I was trying to let her lose gracefully.

Two rounds in, it hit me. She hadn’t learned a thing. She couldn’t explain the game to her three-year-old brother any better than he could explain it to her. She went along for the ride. She never bumped into a rule, so she never learned one.

That’s what we’ve done with Christianity in much of America. We’ve sanded it down so smooth that nobody catches on anything. No friction. No correction. No one hears, “You can’t move there — here’s why.” And the result is a faith so bland it can’t be told apart from the background noise. Jesus has a word for that. He calls it salt that has lost its taste.

But Jesus didn’t come to throw out the rules. He came to fulfill them — to bring them to their intended goal. And then he gave us the only righteousness that actually works. Here’s what I want you to see today: the Law still matters. It still teaches, corrects, stings. But it cannot save you. Only Christ can do that. And because he has, you’re free to be salt in a world that has forgotten what the rules are for.

To understand what Jesus means, we need to hear what Isaiah was shouting six hundred years earlier.

[THE PROBLEM] — The Fast That Fools No One

“Cry aloud; do not hold back; lift up your voice like a trumpet; declare to my people their transgression” (Isaiah 58:1).

God tells the prophet to shout. Not whisper. Not suggest. Not “share his truth.” Shout. Because the people were doing everything right — on the surface. They fasted. They prayed. They bowed their heads like a bulrush bent in the wind. They showed up for worship. And the whole time? “Behold, in the day of your fast you seek your own pleasure, and oppress all your workers” (v. 3b).

The Hebrew word for “fast” — tsom — appears seven times in this passage. The people throw it in God’s face like a receipt: “Why have we fasted and you have not seen it?” They expected God to be impressed. They had done the religious thing. They had punished their bodies, skipped their meals, worn the sackcloth. Surely that counts for something.

But here is what God says: “Is such the fast that I choose, a day for a person to humble himself? Is it to bow down his head like a bulrush, and to spread sackcloth and ashes under him? Will you call this a fast, and a day acceptable to the LORD?” (v. 5).

Do you hear the edge in that question? God is not asking for information. He is answering it. No. That is not a fast acceptable — ratson, the Hebrew word, meaning “pleasing, delightful” — to the LORD. Not because the fasting was fake. They really did go hungry. The sackcloth was real. The ashes were real. But like the checkers app, the whole system let them glide through without being changed by it. They performed religion without being corrected by it. The Law was there on paper. It just wasn’t working on them.

John Chrysostom nailed this in the fourth century: “Do not say to me that I fasted for so many days, that I did not eat this or that, that I did not drink wine, that I endured want; but show me if from an angry man you have become gentle, if from a cruel man you have become benevolent. If you are filled with anger, why oppress your flesh? If hatred and avarice are within you, of what benefit is it that you drink water?”

Chrysostom understood what Israel wouldn’t face: you can afflict the body while the heart remains untouched. You can fast from food and feast on resentment. You can bow your head in prayer and keep your boot on your neighbor’s neck.

This is not ancient Israel’s problem. This is ours. We have built churches — good churches, faithful churches — where a person can attend for years and never hear that they are a sinner who needs a Savior. Where “God loves you just as you are” has quietly replaced “Repent and believe.” Where the Law has been smoothed down until it corrects no one. No friction. No sting. No learning.

And the result? The same as my daughter’s checkers game. We can’t explain the faith to our neighbors because we were never taught the rules ourselves. We went along for the ride. I do this. You do too. We all prefer the frictionless version. It’s more comfortable. But comfortable Christianity produces Christians who don’t know what they believe or why it matters — and who have nothing distinctive to offer the person next door.

Do you see what God is saying through Isaiah? He’s not angry that they’re fasting. He’s angry that their fasting isn’t changing them. The rules were right there. The Law was given. But it slid right off them like water off a stone. And a faith that doesn’t correct you can’t save you either.

So what does God actually want? And where does this leave us — people who can’t even keep the rules we’ve been given?

[TODO: The Turn — “Not to Abolish, but to Fulfill” (πληρῶσαι), The Gospel — Christ’s Righteousness Given to Us, Living in the Light — Salt in the Valley, Conclusion — Back to the Board]