“…a burnt-offering, a fire-offering, a satisfying aroma to Hashem.” (Lev.1:9)
R’ Yaakov Tzvi Mecklenberg explained that a person shouldn’t think that s/he achieves forgiveness with their sacrificial offering. Rather, it is to be an aroma, a scent of the changed life that will now commence. You encounter the smell of something before you encounter the thing itself. So too, the sacrifice must presage personal transformation in the sinner.