Why You Cannot Trust Your Own Heart

Last time we looked at sin as a condition and not just actions, something every person is born into rather than something we each invent from scratch.

But a condition has to live somewhere.

Keep your heart with all vigilance, for from it flow the springs of life.

Proverbs 4:23

What Jesus got to the heart of the commandments

In the Sermon on the Mount, Jesus took commandments everybody in the crowd already knew, and extended them to conditions of the heart.

You have heard that it was said to those of old, “You shall not murder; and whoever murders will be liable to judgment.” But I say to you that everyone who is angry with his brother will be liable to judgment.

Matthew 5:21-22

It was now not just about not committing an act of sin such as killing, Jesus exposed the source, even if you hold anger in your heart you will be judged, because it is out of this condition that the outward sin occurs.

A few verses later He does the same.

You have heard that it was said, “You shall not commit adultery.” But I say to you that everyone who looks at a woman with lustful intent has already committed adultery with her in his heart.

Matthew 5:27-28

Jesus does not stop at the act of sin but digs deeper, lust is the seed of adultery and you have to kill it because you will be judged for it.

Actions can be managed. A disciplined person can stay in line for years and act as they know they should, but their heart is untamed, and the condition of their heart is easily hidden because no man can see it, and this is what Jesus says God will judge.

The word reaches where nothing else does

So how can I fix something I cannot see or touch?

For the word of God is living and active, sharper than any two-edged sword, piercing to the division of soul and of spirit, of joints and of marrow, and discerning the thoughts and intentions of the heart.

Hebrews 4:12

The word of God can do the work. It pierces. It divides. It discerns.

That last word is κριτικός, kritikos, meaning able to judge or sift. It is where we get critic and criteria. Scripture sifts what is going on inside a person, in places that person cannot see clearly themselves.

And no creature is hidden from his sight, but all are naked and exposed to the eyes of him to whom we must give account.

Hebrews 4:13

We will be naked and exposed, with our hidden motives, quiet preferences, old resentments, the things we have told no one.

God cannot be deceived by managing a reputation. He cannot be satisfied by outside behavior or by playing the part of a good person. God is looking at your heart, and it is from the condition of your heart that you will be judged.

Your mouth is telling on you

If you want to know what is in your heart, Jesus tells you how. Listen to yourself talk.

You brood of vipers! How can you speak good, when you are evil? For out of the abundance of the heart the mouth speaks. The good person out of his good treasure brings forth good, and the evil person out of his evil treasure brings forth evil.

Matthew 12:34-35

Out of the abundance of the heart the mouth speaks. Your words are never only words. They carry up whatever the heart is full of. Fill a heart with the love God actually asks for, with gratitude and trust, and the words will show it. Fill it with bitterness and pride and self-interest, and the words will show that too.

Which is why managing your speech will never be enough by itself. You can guard it for a while. Sooner or later the heart will speak.

So listen to yourself this week and learn from it. The complaints. The criticisms. The way you talk about people who are not in the room. The way you talk about yourself. The way you talk about God. Every one of those is a window, and every one of them is telling you something about what is happening in your heart.

The witness you should not trust

The heart is deceitful above all things, and desperately sick; who can understand it?

Jeremiah 17:9

Deceitful above all things. It deceives other people, and it deceives you about yourself.

So the question am I doing alright spiritually? put to your own heart is maybe not the best witness. The heart will often report back what you want to hear. It will minimize your real sins and magnify everybody else’s. It will explain why this particular pride is not really pride, why that anger was justified given the circumstances, why the unkindness was mostly the other person’s fault anyway. And it will do it with confidence.

This is exactly why Scripture and the Holy Spirit are needed to do work the heart cannot do for itself. The word exposes and cuts. It helps us realign, and gives us something to aim for. The Spirit presses on the conscience and brings up things we need to address, often through other people.

Search me

David knew this about himself.

Search me, O God, and know my heart! Try me and know my thoughts! And see if there be any grievous way in me, and lead me in the way everlasting!

Psalm 139:23-24

It is God who can properly search, try, see and lead us.

David had learned he could not trust his own measure of himself, and handed it over to God, who would expose the truth he needed to hear and mold him into a godly man.

So I will leave you with this. Ask to be searched by God, the only One who can truly see you and where your heart is and allow Him to lead you to be remade in His image.

Next week, the sinful nature does not leave, it stays, and it keeps fighting.