Offering a Sacrifice
Ramban stresses the importance of a person’s intentions and feelings when offering a sacrifice. This is further emphasized by the explanation that a sacrifice serves to bring a person’s attributes—both intellect and emotion—close to God.
However, this begs the question: If the main purpose of a sacrifice is to evoke the appropriate feelings, then why does the Torah mention only the physical details of a sacrifice, and totally omit the emotional and intellectual demands which an offering to God entails?
It could be argued, however, that the Torah did indeed hint to the emotional element of the sacrifices, by recording the voluntary offerings (chaps 1-3) before the obligatory offerings (chap. 4 ff):
At first glance, this appears to be quite puzzling: Surely the Torah should have instructed us first about offerings which must be brought before detailing the optional sacrifices?
With an obligatory sacrifice, a person could be carrying out the mitzvah merely because he has to. With a voluntary sacrifice, the very fact that a person is bringing an offering when he is not required to do so testifies that his intentions are good. Therefore, the Torah recorded the voluntary offerings unexpectedly at the very outset, to teach us that just as a person’s good intentions are self-evident in the case of a voluntary offering, likewise good intentions are of paramount importance with all offerings.
(Based on Likutei Sichos vol. 17, pp. 12-13)