On the Mount of the Transfiguration we have a perfect response to the law and the prophets. The response is called Jesus Christ, and that response is called: Good news! Gospel!
Moses, the face of the law, is on the mountain with Jesus. So is Elijah, the face of the prophets. They are there with Jesus, the face of the Gospel.
We've met Moses.
We've met Elijah.
That is, we know the law. We know we fail miserably to keep it.
We've heard the prophet. We know we're called to holiness. We know we've failed miserably to live righteously as we should.
Now meet Jesus.
He kept the law of God -- perfectly.
He lived a life of holiness -- perfectly.
And -- wait for it -- the good part, is that God has agreed to accept his perfection on our behalf.