“Sruti says sarvam papmanam tarati brahmahatyam yo ’svamedhena yajate: he who performs a horse sacrifice is purified of all sins, even the sin of killing a brahmana. Therefore you can purify yourself by a horse sacrifice.”

Just as thick mud cannot purify muddy water, and an object made impure by contact with wine cannot become pure by washing it with a lot of wine, one cannot be purified of killing by the performance of many sacrifices which has intentional killing of animals as a major part.

********** Chapter Nine Passing of Bhisma