You see, the Witch knew of the Deep Magic from the Dawn of Time. But she was not aware of the Deeper Magic from Before the Dawn of Time, as Aslan explained it to Susan and Lucy.
He said that according to a decree from before the Witch’s time, “when a willing victim who had committed no treachery was killed in a traitor’s stead, the Table would crack and Death itself would start working backwards.”
And “all have sinned and fall short of the glory of God” says Romans 3:23, but verse 24 goes on to say that we are made right with God “...as a gift by His grace through the redemption which is in Christ Jesus...”
That’s right. Jesus Christ came to us as a Lamb for sacrifice, and just when Satan thought he had won, when God seemed momentarily weak and the devil held all the cards, in that very moment God was working the Deeper Magic from Before the Dawn of Time, determined in the Divine Council of the Trinity before the foundation of the world (I Pet 1:18-21), and when the first hammer struck the first spike to nail down the hands of the Savior, God was striking His blow against Satan and Sin and Death and the Grave and from that moment on Death has begun to work backward.