Translation by Yehoshua Siskin
Dr Rakefet Ben-Yishay writes: "Whoever has tried to diet knows that the most difficult problem is when we eat just a small bite of something 'forbidden' and immediately afterwards we say to ourselves that, in any case, we have already messed up, the diet is over, and we can now go back to eating without limit. This is sad since the first bite that we took was negligible from the standpoint of calories and it could not by itself destroy our diet. The problem was what we said to ourselves after we took that bite. We allowed it to distract us from the road we had chosen and so it really did destroy our diet.
This mistake also occurs in the emotional and spiritual domain. In Ki Teitzei a series of sinful occurrences is described that appear to have no connection between each other. Yet Rashi explains that the Torah put them together in order to demonstrate an important principle - one transgression leads to another and every sinful act leads to a more serious one. The main problem with sin is not the sin itself, but what it brings in its wake. A person feels that because of a sin he is a failure and has distanced himself from other people or from God. Despair begins to gnaw at him and he believes his situation is irredeemable. This mindset of 'everything or nothing' brings him to continue to err and to sin since, in any case, he thinks he's disqualified and no longer in the game.
But this is a false notion. No one is ever a failure. The Torah tells us that at every stage and at any point it's possible to start over. This is especially true during the month of Elul. Even if you took one extra bite, even if you went down the wrong road, you can always stop and change direction."