Jesus taught that our reason for doing a particular act matters a great deal. For instance, He said there wouldn’t necessarily be a reward, other than perhaps a feeling of personal satisfaction, for being kind to someone just because they’re kind to you (Matthew 5:46). The flip side – showing kindness to those who mistreat you – will yield heavenly reward. On a related note, Jesus also taught as read in Matthew 6:1-18 that doing religious things (e.g. fasting, praying, or giving) for the purpose of being spiritually elevated in the eyes of others’ is equally pointless. So, intent will determine whether an action will be fruitless or rewarded.
Intent – the reason for doing a particular deed – can be as important as the act itself and is a key ingredient to sin! In fact, Jesus reported that the intent to do something can be as bad as the intended action – even if it isn’t carried out. In the following passage, He informs us that if we intend to commit adultery, we’ve done it even if the act wasn’t completed. I know that some people have exclaimed that the passage implies we’ve committed adultery if we privately acknowledge that a woman is ‘hot’ in a fleeting thought, but that wasn’t Jesus’ point.
“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 lust for her [desires to have her] has already committed adultery with her in his heart.” —Matthew 5:27-28. (The comment in brackets was inserted by me and is based on the Strong’s definition of ‘lust’)
Again, Jesus’ point was to teach that once we intend do take sinful action, it’s as good as done. Understand that a thought in itself isn’t wicked as long as it doesn’t give way to an intention to take action.
How do we ensure a thought doesn’t mature into lustful intent? Internalize God’s ways through study, prayer, meditation, and fellowship so that they become a force greater than physical desire.
Jesus also taught that the heart (mind) gives birth to all kinds of sinful things; this serves as a reminder that rebellion/sin is intentional and begins the mind.
“But the things that proceed out of the mouth come from the heart, and those defile the man. For out of the heart come evil thoughts, murders, adulteries, fornications, thefts, false witness, slanders.” —Matthew 15:18-19.
We must always be aware of our intentions and how what we’re going to say or do will affect others. Having a good understanding of God’s ways will help us to know whether something we intend to do or say can result in sinful behavior. That understanding is gained through physical exposure to God’s instructions and spiritual communication through His Spirit.
How do you maintain righteousness and a pure intent?
Equipping believers to become followers through discipleship! 
As you have surmised and/or quoted the words of the savior, I agree with every one of them. And yet, this raises the question, if a sinful thought about a woman is identically as evil as a sinful deed with a woman, and yet there are disparate amounts of prurient reward gleaned between the two, why would one not weigh the consequences (equal guilt/displeasure) and have more pleasure for the guilt? That is, if one is going to be punished equally for taking one dollar or twenty, one might as well take the twenty.
In 1 Corinthians 6, Paul uses the example of being united with the body of a prostitute and shuns the concept, being that the body is the temple of the Lord. It does seem to create a barrier that adds perspective to the words of Christ, saying that both are sins but perhaps that both are not *equal* sins. The internet has brought unprecedented access to the enemy in every man’s struggle, but I have fiercely championed virginity/purity as a lifestyle. If I am to be told the fleeting moments of thought were equal to the deed, where is the incentive to avoid the deed?
Great comment – very insightful.
A fleeting thought on its own isn’t the problem – it’s what we do, or intend to do, with that fleeting thought that’s the issue and potential sin. By the time someone thinks about committing sin (like adultery or murder) and that desire turns into intent, they’ve made the choice to commit the act.
My ‘intent’ was to show that Jesus linked a desire to accomplish an act to the actual physical act. This is different, and worse, than a fleeting thought and why, for instance, the intent to commit murder may earn someone the same penalty as they would’ve gotten had they completed the act.
Thanks again for your excellent comment!
Blessings. rb