This week is the second week in the series, Exposed.  Pastor Scott talks about Atonement and the Blood of Christ and answers the question; Why did God have to offer Jesus as a sacrifice for our sins? - to demonstrate His justice.  Bottom Line; Payment had to be made in the form of Jesus's Blood to cover human sins -

Because of God's mercy, He delayed payment,

Because of His Justice, He demanded Payment,

Because of His grace He made the payment.