You have heard that it was said, ‘You shall not commit adultery.’ But I tell you that anyone who looks at a woman lustfully has already committed adultery with her in his heart.
Matthew 5:27-28 NIV
In Matthew 5:20, Jesus sets a sobering threshold. He tells us that unless our righteousness surpasses the Pharisees’, we cannot enter the kingdom of heaven. True righteousness begins in the heart — not in religious performance or rule-keeping. That is the standard to which Jesus calls us.
This means it is entirely possible for a person to appear righteous outwardly and yet still miss heaven. The Pharisees were disciplined and strict in their religious observance. Yet Jesus identifies their righteousness as insufficient. He then gives us a window into why.
True Righteousness Begins in the Heart, Not the Act
In Matthew 5:27-28, Jesus refers to the commandment: “Do not commit adultery.” Then He raises it: “Anyone who looks at a woman lustfully has already committed adultery with her in his heart.” The sin, He says, exists before any physical act. It begins in the thought, in the gaze, in the hidden intention.
So it is not enough to excuse sin simply because you have not yet carried it out. The man on the inside — the mind, thoughts, and inner motivations — is Christ’s primary concern. God does not merely measure what others can see. Indeed, He measures the whole person, from within outward.
True righteousness begins in the heart because all actions flow from there. What a person is on the inside shapes how they think. And how they think ultimately shapes what they do and say. Jesus affirms this in Matthew 12:34. Out of the abundance of the heart, the mouth speaks.
So the goal is not merely to restrain outward sin. The goal is for the inner man to produce good fruit. That inner fruitfulness shapes everything visible — where your feet go, what your mouth says, and what your hands reach for. Furthermore, Jesus has already paid the full price for sin, once and for all. He therefore calls us to live within that finished work. This means not drawing repeatedly on His sacrifice for deliberate, habitual patterns of sin. A person genuinely aligned with God will not continually dwell in thought patterns that lead to sin. The alignment must begin in the mind. As a result, even a sinful thought — one you have not yet carried out — can constitute sin before God.
Living It Out
Guard the inner life. True righteousness begins in the heart, and that is precisely where you must cultivate God-honouring transformation. What you allow your mind to dwell on will eventually shape everything else.