The pasuk says (Vayikra 5:15 & 21) “If a person will commit a misuse (מַעַל) and sins (חָטְאָה) unintentionally against Hashem. In pasuk 21 it says “If a person will sin (תֶחֱטָא) and create a trespassing (מַעַל) against Hashem”
The Chida notes that in the first pasuk מַעַל (misuse) is followed by חָטְאָה (sin), whereas in the second pasuk the order is reversed. He asks, what are we to learn from this change in order? He quotes a source to say that many times a person commits a sin intentionally, knowing that it is wrong, yet somehow or another he justifies it to himself, and thinks that it will be a “one-time only” event. Unfortunately, once the person sinned, he also lowered his guard for this sin, making it much easier for this sin to happen accidentally in the future. Therefore, the reading of the pasuk is “a person who did a sin ‘on purpose’ (ma’al) can lead to a sin (chatas) accidentally.” The second pasuk adds to this and teaches us that the same is true in the reverse. If a person commits a sin by accident, though he may be truly appalled by what he has done, he nevertheless lived through it. This can lead to his subconsciously letting down of his guard down, thereby allowing the yetzer hara to weasel its way in to his heart and cause him to do the sin on purpose.
The message that the Chida is telling us is that association brings further association, and one must be careful to have only positive associations. There is a famous Chinuch which discusses this idea in regards to mitzvohs that are “Zecher liyetzias mitzrayim” – that cause us to remember the exodus from Egypt. The words which he uses which are famous are: Adam nifal lfi peuloso:מצוה טז a person will be affected and act in accordance with the actions which he has done. Meaning, not only are we creatures of habit, but we are internally effected by our deeds.
Probably the most intense and enjoyable time on the Jewish calendar is Seder night. This annual event is etched into the memory of every individual. The better we prepare ourselves for that association, the greater effect it can have on us. As we clean for Pesach (the mess that we made of our lives throughout the entire year), we should do it with devotion. We know that there is a double meaning in the word, chometz. It means the actual chometz and it also refers to the yetzer hara. Being careful not to have even a morsel of chometz should represent our desire to rid ourselves of the yetzer hara as well. This should help us merit to be affected the mitzvohs empower our yetzer hatov.