Castiel nodded briefly. "You are correct. My grace is like energy. It is where I derive my powers, how I can speak to my Father and my siblings. It holds my form when I am not in a vessel. It is a gift from my Father, a part of Him."
He was glad he had shown her his wings. It was the first time he had shown them to someone who already believed him.
"Like all gifts it comes with a responsibility too." He looked a little tired as he hung his head. "But my mission has given me a chance to meet people I would normally not even be able to speak to. I have heard Dean say that he would not change his experiences even though they are difficult. I am beginning to understand that."