http://revach.net/article.php?id=5310

Section: Taryag Mitzvos   Category: Taamei Hamitzvos
Sefer HaChinuch - What Does Killing an Animal Do For Us?

To bring a Korban is considered the pinnacle of Avodas Hashem in this world. The word Korban is from the word Karov, as it brings us close to Hashem. Tefila, which is one of the three pillars of the world, is merely a replacement for Korbanos now that the Bais HaMikdash is not standing. What is it about animal slaughter that has this incredible spiritual effect? Since when does Hashem desire us to engage in violent and bloody activity?

The Sefer HaChinuch explains that the only thing separating us from animals is our intelligence. Other than that we are both physical beings that like to indulge in worldly pleasures. A human is meant to use his intelligence to serve Hashem, and when we go astray it is because we have ignored our intelligence and acted like an animal.

Our intellect is eternal and will always remain, long after our physical bodies have expired and become part of the dust of the earth. When we do an aveira we need a reminder of this lesson. We take an animal, which represents our mortal half, and burn it to remind us that it is pointless to serve our physical half. We would be wise to concentrate our efforts on our intellect, the part that makes us unique and eternal.

As our intellect is a Cheilek Elokai MiMaal, a spark from Hashem, when we choose our intellect over our bodies we are by definition becoming closer to Hashem. That is the definition of a Korban.