Exodus 29:10

To signify that they offered it for themselves and for their own sins, which the offerer performing this rite was to confess, Leviticus 16:21, that they acknowledged themselves to deserve that death which was inflicted upon this innocent creature for their sakes, and to testify their faith in the future sacrifice of Christ, upon whom their sins were to be laid, and by whose blood they were expiated, and that they humbly begged God's mercy in pardoning their sins, and accepting them to and in their holy office.