Sforno on Leviticus 5:17/ספורנו על ויקרא ה׳:י״ז

1ואשם ונשא עונו, our sages have a tradition that the Torah here speaks of an asham taluy, a guilt offering offered while the exact nature of the guilt is unclear. The person offering it is not even sure that he is guilty of an offence. Considering this state of affairs the Torah writes ונשא עוונו, he carries (the burden) of his guilt. The guilt is not spelled out precisely as it is not yet known. He may not actually have committed a sin, but this does not mean that he is free from guilt as had he been careful he would never have been in the predicament of not knowing if he had committed the specific sin he is afraid he might have committed.