How Do You Know If You’re Building On The Rock and Not The Sand? (Matthew 7:26)

What does Jesus mean when he says we must ‘act on these words of mine’?

Posted on June 18, 2026 by Paul Ellis // 0 Comments

Jesus said, “It’s not enough to hear my words, you need to act on them” (see Matt. 7:24).

Okay, but what sort of action did Jesus have in mind? What words are you supposed to do? You need a good answer to this question lest you be like the foolish man who built on sand and lost his house.

Christ’s challenge to act on his words comes from the well-known Parable of the Wise and Foolish Builders, which he delivered at the end of the Sermon on the Mount. Some people read this parable as a call to earn your salvation:

To be saved, you have to do everything Jesus says in the Sermon on the Mount. You have to turn the other cheek, love your enemies, never get angry, go the extra mile, forgive those who sin against you, don’t worry, don’t judge, and don’t sin. Fail to do all these things and you are doomed to destruction.

This is pure law. It is not good news. It is bad news because if you try and do everything Jesus said in the Sermon on the Mount you will fail, your conscience will condemn you, and you won’t be saved.

Others take a different approach. They say, “We must do everything Jesus says in the Sermon on the Mount to become mature believers.” But no one was ever saved or sanctified through their law-keeping or good works (Rom. 3:20). Pretending to live by law will not make you a mature believer. It’ll just make you miserable.

Everyone who hears these words of mine and acts on them, may be compared to a wise man who built his house on the rock. (Matthew 7:24)

When Jesus refers to “these words of mine,” he’s not talking about some law. He is referring to what he has just said about doing “the will of my Father” (see Matt. 7:21). And the will, the work, and the command of the Father is to believe in the Son he sent (John 6:29, 40, 1 John 3:23).

Do you see? This is really good news. You don’t have to struggle and strive and hope your best is good enough (it isn’t). You just need to trust that everything that needed to be done to save and sanctify you was accomplished through the Son God sent.

Who is the foolish man?

The foolish man is the one who hears about the will of God but doesn’t do it. He hears the good news of grace but doesn’t believe it. Instead of trusting in the finished work of the cross, he’s trusting in his own works. And this is why he falls.

A wise person builds on Jesus, the Righteous Rock, but a foolish person builds on the shifting sands of self-righteousness. Refusing to believe that every blessing is freely ours in him (Eph. 1:3), they strive to earn the acceptance, salvation, and favor of God.

No one wants to be a fool. We all desire wisdom and Jesus tells us how to get it. “If you want to be wise, do the will of God.”

In other words, don’t just hear the good news; believe it.

Like the Jews who heard the Sermon on the Mount, many of us have heard that we must work to prove our worth to God. But the only work that God is looking for – the work that accompanies our faith – is that we believe in his Son.

This is the work of God, that you believe in him whom he has sent. (John 6:29)

Wise or foolish – which are you?

This week I posted something on Faceook that proved to be far more controversial than I imagined: “What is the work of God? Simple – believe in Jesus.”

Oh. My. Word.

More than 20,000 people saw that post and judging by the angry comments it attracted many of them did not think that believing in Jesus is the work that God desires. Oh no, they said. Believing is just the beginning. We also have to repent, confess sins, die daily, love our neighbors, tithe, keep the commands, surrender, prayer regularly, and do all the other things in the Bible.

Which makes me wonder how they might have reacted to Jesus when he first uttered the famous words of John 3:16. “Whoever believes in him shall not perish but have eternal life.”

Let us be clear: A foolish person is someone who either doesn’t believe or believes that believing is not enough – which is to say they don’t believe.

A foolish person works because they have not seen the work of Christ. A foolish person worries that when Jesus returns their shortcomings will be exposed. A foolish person has no peace and no confidence because they are not walking in the will of God.

In contrast, a wise person believes, which means they don’t toil and strive to save themselves or make themselves holy. A wise person trusts, which means they are settled and at rest. A wise person has confidence and looks forward to the day Jesus will return.

The foolish person trusts his works, but the wise person trusts in Christ’s finished work.

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Several years ago, I read a brilliant—and somewhat scary—sermon by C.H. Spurgeon titled, “A Blow at Self-Righteousness.” I thought it was such a powerful message that I edited it to make it more accessible to modern readers. This week marks the anniversary of C.H. Spurgeon’s birth. To celebrate the occasion, you can download this historic sermon FREE from my Patreon page. Be quick – this offer ends Sunday.