It is a debt that needs to be collected no matter what.
Aslan was grave and sad but a decision was made. He gave himself in place of Edward who betrayed him before even knowing Him.
The White Witch and her followers muzzled him and mocked him, pierced him and shaved him. He was not the King of Lions they laughed, but a mere cat.
Aslan could take off three or four arms with one bite, shake them to their knees with one roar, but He didn't. He chose to bear it for Edward.
He was bound and tied to the Stone Table, and the White Witch took his life.
The first to care for his lifeless body, to wipe away the Blood that was shed to save Edward was Lucy and Susan.
They cried as they tried to unbind the lifeless Lion, but the face was no longer sad, but a calm rest.
Then a thundering sound, echoed through the woods. The Stone Table cracked. The veil between the White Witch's terror and Aslan's power was no more.
Aslan's roar shook the ground and trees bent and bowed to him. Enemies ran and hid knowing He has returned. Aslan's breath brought life back to the dead, His touch light the flame to the hardened souls of those who were lost.
The war was won, the White Witch fled, the kings and queens who ruled by Aslan's Laws prospered and blessed.