What role does the law play in the doctrine of substitution?

The law serves as a judicial standard in the doctrine of substitution, requiring that justice be served for sin. According to Romans, the wages of sin is death, highlighting the necessity of a perfect substitute. In the narrative of Barabbas, we see how justice is satisfied—Barabbas' sentence is carried out not on him, but on Christ, who bore the penalty of sin for His people. This illustrates the fulfillment of the law through Jesus, positioning Him as both the lawgiver and the one who meets its demands perfectly.