Some say thoughts aren’t sins unless you put them into action, but I’m not sure. Of course, what I or someone else thinks about thoughts isn’t worth much, so let’s see what Jesus says about it.
In Matthew 5:21, 22, our Lord says, “Ye have heard that it was said … Thou shalt not kill; and whosoever shall kill shall be in danger of the judgment: But I say unto you, That whosoever is angry with his brother without a cause shall be in danger of the judgment.” He’s not actually calling someone like this a murderer, but He’s discussing the importance about thinking angry thoughts.
Now jump down to verse 27. “Ye have heard that it was said … Thou shalt not commit adultery: But I say unto you, That whosoever looketh on a woman to lust after her hath committed adultery with her already in his heart.” Here the Lord is telling us that sin is not always an action, it’s an attitude. It’s thoughts.
In the Sermon on the Mount, our Lord spent a lot more time talking about the attitude of pride and arrogance and sinful thoughts than the actual deeds, because every sinful deed originates with a thought in the mind. So if we’re going to squelch sin, we need to begin by asking the Lord to get our minds and our thoughts captive to the Holy Spirit. That’s where all sin originates.