RAV KOOK ON VAYIKRA Part 1 Sacrifices vs. Fasting

When the fourth-century scholar Rav Sheshet fasted, he would add the following request to his Amidah (Standing) prayer: "Master of the Universe! You know that when the Temple stood, a person who sinned would bring a sacrifice. Although only the fats and blood would be offered on the altar, the person would be granted atonement. "Now I have fasted, and my fat and my blood have diminished. May it be Your Will that the decrease in my fat and my blood should be considered as if I offered them on the altar, and my offering was accepted." (Berachot 17a) Rav Sheshet's prayer is inspiring, but it makes one wonder: Why should one go to the trouble of bringing a sacrifice if the same atonement may be achieved through fasting? His prayer draws our attention to a second issue. Why were only the fats and blood of sin sacrifices ( chatat and asham) offered on the altar?