Answer
The Bible says that the law is a schoolmaster that points us to Christ, that brings us to him, prepares us for him. The law is given, and it's a reflection of God's character, but we fail to keep the Law. And so, when Jesus comes he shows us perfect humanity fulfilling its intended purpose, which is relationship with God typified with faithfulness to God's commands. So, Jesus comes showing us true humanity in the way it's supposed to be, but also fulfilling that law for us. Jesus fulfills the Law in his continual faithfulness to covenant keeping, law-abiding behavior, so that he becomes our righteousness. The Bible says that God is both just and the justifier. And so, he comes with his law, and then he comes with his Son keeping the law for us. So, he both is the just one, and the one who justifies us in Christ.
Answer by Dr. K. Erik Thoennes
Dr. K. Erik Thoennes is Professor of Biblical and Theological Studies at Biola University’s Talbot School of Theology.