“…Hashem will forgive her because her father has restrained her.” (Bamidbar 30:6)
Rashi tells us that though the vow was annulled and the woman was unaware of this, she in her mind’s eye transgressed a vow. She needs repentance because she thought she was sinning, even though she wasn’t.
The Chasam Sofer asks “The gemora in Kiddushin tells us that if a person thought to do a sin but did not do it, he is not punished. Essentially there is no sin. Here too, this woman thought she was doing a sin and did not do one, so why should she need atonement?” He answers that there is a great distinction between the two situations. In the gemora in Kiddushin, she only thought about doing a sin, but there was no action taken. In our case, an action was taken with the thought that it would be a sin, it just turned out not to be a sin. Therefore we understand when Chazal tell us “An evil thought strengthens the action” it does not have to mean that the action was actually a sin, but even an action with the intent of it being a sin is a negative act.
I think that this needs a bit more explanation. What is the difference at the end of the day? No sin was actually performed in either case! The Chinuch tells us: ״כי האדם נפעל כפי פעולותיו.” (A person is affected by the way he acts). This means that the way a person normally acts, even if it he acts only half-heartedly, will eventually bring him to live what his actions represent.
I once heard from a member of Hatzlala who was considering leaving his post because he was concerned that if his children see him “desecrate” the Holy Sabbath day week in and week out (though in reality, not only is it not a sin, but what their father is doing is a mitzvah), their reverence for Shabbos just will not be the same as someone who never saw another Jew desecrate the Sabbath in his entire life. Obviously, one could argue that it is not a desecration of the Sabbath! Whether or not that is true has nothing to do with what a small child sees, as he will come to understand that the Sabbath can be desecrated in certain situations and will become desensitized to it.
When one thinks one is sinning, whether it is technically forbidden or permissible, the defiance of the Will of Hashem is clearly embedded in the mind of that person who did the action.
As we approach Tisha B’Av, the Sefarim Hakadoshim tell us that we should increase our actions that show our distress of the destruction of the Beis Hamikdash. Even though they may start out as hollow actions, these actions eventually take root and become meaningful to us, and will cause us to feel the loss of the Holy Temple.
There are those people who say that if it is not genuine, then G-d does not want your service – or your tears. I think the simplest proof against this is the famous Chazal: mitoch shelo lishma ba lishma (doing something for non-altruistic reasons will bring someone to do them altruistically). I believe that this is what the Chasam Sofer was alluding to, when he said that the thought is attached to the action. As we take actions or refrain from doing things at this time of year, whether it is dancing, playing music, taking a haircut, or bathing, if we stop to think about it, not only will it make those observances more meaningful, but it will actually make our hearts yearn for the rebuilding of the Holy Temple in Jerusalem – may it happen soon in our days!