The Old Testament system of sacrifices was a graphic and repetitive reminder of the severity of sin, and of the requirement that blood be spilt in order to obtain atonement and forgiveness. Since Jesus Christ, the Lamb slain from the foundation of the world, offered himself as the unique and completely efficacious sacrifice that need not be repeated, there is no need for continued sacrifices.
Yet can we say that the need for men to be reminded of the severity of sin and of its drastic consequences — as well as the sufficiency of the gospel to repair the God/man breach — has been eliminated after the Cross?
If not, under the New Covenant in Christ what serves to teach men about sin?