To show that even before the new testament JESUS was meant to die for our sins.
Who died for your sins?
JESUS CHRIST. 2 Corinthians 5:21
2 Corinthians 5:21 (Amplified Bible)
For our sake He made Christ [virtually] to be sin Who knew no sin, so that in and through Him we might become [endued with, viewed as being in, and examples of] the righteousness of